College  of  ^fjpsicians  anb  burgeons; 


m'^ 


P1^ 


SANITAEY  UEXAMINATIONS 


OP 


WATEE,  AIE,  AND  FOOD 


U,        iiJ-J-ll, 


SANITARY  EXAMINATIONS 


OF 


WATEE,   AIE,   AND    FOOD 

WITH  ONE  HUNDRED  AND  TEN  ILLUSTRATIONS 


By  COENELIUS  B.  FOX,  M.D.,  r.E.C.R  Lond. 

FORMERLY  MEDICAL  OFFICER  OF  HEALTH  OF  EAST,  CExNTRAL,  AND   SOUTH  ESSES 


PHILADELPHIA 
P.   BLAKISTON,   SON^,   &    CO. 

1012  WALNUT  STREET 
1887 


F2  3 


TO 

JOHN    SIMON, 

C;B.    D.C.L.    F.E.S. 

WHOSE  LABOUES  IN  THE  DEVELOPMENT  OP 

THE  SCIENCE  OF  PREVENTIVE  OR  STATE  MEDICINE 

MERIT  THE 

GRATITUDE  OF  ALL  MEN  OP  ALL  NATIONS 

THIS  VOLUME 

IS 
WITH  HIS  PERMISSION 

DEDICATED 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/sanitaryexaminat1887foxc 


PEEFACE  TO  SECOND  EDITION 


The  universal  recognition  of  the  utility  of  this  work,  not 
only  by  Medical  Ofiicers  of  Health,  for  whose  assistance 
it  was  written,  but  also  amongst  that  portion  of  the 
public  which  is  interested  in  the  promotion  of  Sanitary 
Science,  has  rendered  the  preparation  of  a  new  Edition 
needful. 

My  retirement  from  the  public  health  service,  in  conse- 
quence of  an  inabihty  to  sacrifice  principle  to  expedi- 
ency, is  not  in  one  sense,  perhaps,  to  be  regretted,  since 
the  enforced  leisure  has  afforded  me  the  opportunity  of 
studying  those  Biological  Methods  for  the  examination 
of  Water  and  Air  that  have  been  introduced  of  late 
years,  and  which  are  considered  by  our  German  and 
French  confreres  to  be  as  important  as  their  chemical 
analysis.  Great  improvements  have  also  been  recently 
effected  in  the  examination  of  Milk. 

My  thanks  are  due  to  those  health  officers  who  have. 


Vlll  PKEFACE    TO    SECOND    EDITION 

in  response  to  my  invitation,  sent  me  memoranda  for  the 
improvement  of  this  Handbook. 

To  Drs.  Shea,  Ashby,  P.  Frankland,  J.  W.  Moore, 
Bond,  Mill,  and  to  the  late  Prof.  Eipley  Nichols,  I  am 
especially  indebted  for  much  valuable  information. 

C.  B.  F. 

Ilfeacombe,  Devonshire,  September  1886. 


PEEFACE  TO   FIKST  EDITION 


The  demand  for  a  third  edition  of  my  brochure  on 
"  Water  Analysis,"  affords  me  an  opportunity  of  offering 
to  the  public  the  results  of  an  increased  and  more 
extended  experience.  The  additions  are  so  great  as  to 
compel  me  to  re-write  nearly  all  that  I  have  pre^dously 
published  on  the  subject. 

The  many  kind  appreciative  comments  that  have  been 
made  on  it  by  the  scientific  world,  and  especially  by  that 
section  of  it  that  is  engaged  in  the  public  health  service 
of  the  country,  coupled  with  the  suggestions  of  friends, 
have  led  me  to  incorporate  with  my  essay  on  "Water 
Analysis  "  sections  on  "  Examinations  of  Air  and  Food." 

I  trust  that  none  of  my  readers  will  imagine  that  I 
have  the  presumption  to  place  myself  forward  as  a  teacher 
of  the  Medical  Officers  of  Health  of  the  country.  I  wish 
rather  to  offer  suggestions  and  hints,  tliat,  I  am  sure,  will 
be  helpful  to  those  who  have  not  plodded  as  I  have,  along 
long,  tedious,  and  tortuous  paths  for  many  years,  at  the 
sacrifice  of  much  time  and  labour,  because  I  could  not 
find  a  short  cut.  It  does  not  follow  that  because  there 
is  "no  royal  road  to  learning,"  that  the  road  which  we 


X  PREFACE    TO    FIRST    EDITION 

have  to   traverse  should  be  beset  with  all  kinds  of  un- 
necessary obstacles  and  difficulties. 

The  objects  which  I  have  kept  steadily  in  view  in 
writing  the  following  pages  have  been : — 

1.  To  avoid  a  consideration  of  these  three  subjects 
solely  after  the  manner  of  an  analyst  who  mechanically 
deals  with  chemical  operations  and  arithmetical  calcula- 
tions, but  to  treat  them  as  a  physician  who  studies  them 
in  connection  with  health  and  disease. 

2.  To  render  such  detaiLs  respecting  examinations 
of  water,  air,  and  food,  as  fall  within  the  province  of  the 
Medical  Officer  of  Health,  so  free  from  technicalities  and 
all  cloudy  and  chaotic  surroundings,  as  to  enable  any 
one  who  possesses  the  average  chemical  knowledge  of  a 
physician  to  teach  himself  by  the  aid  of  this  vacle  mecum 
of  the  health  officer. 

Some  of  the  information  contained  in  this  book 
treating  of  the  examination  of  water  and  milk,  may  also 
be  found  in  other  analytical  works,  amongst  which  may 
be  mentioned  Mr.  Wanklyn's  "  Water  Analysis "  and 
"  MHk  Analysis." 

It  affords  me  much  pleasure  to  acknowledge  with 
gratitude  the  assistance  rendered  to  me  by  scientific 
men  throughout  the  country,  amongst  whom  may  be 
mentioned  Drs.  Attfield,  Barlett,  Brown,  Cameron,  F.  de 
Chaumont,  Hill,  Shea,  Thorne,  Tidy,  and  Messrs.  Dixon, 
Slater,  Thomas,  etc. 

Chelmsford,  May  1878. 


CONTENTS 


PAGE 

Preface  to  Second  Edition     .  .  .  .       vii 

Preface  to  First  Edition        .  .  .  .        ix 

Introductory  Observations      ....         1 


SECTION  I.— SANITAEY  EXAMINATION  OF 
A  DEINKING  WATEE 

CHAPTEE    I 

The  Wholesomeness  of  a  Water 


CHAPTEE  II 

The  Determination  of  the  Amount  and  Nature  of 

THE  Organic  Matter           .             .  .  .13 

1.  The  SmeU  of  a  Water   .             .  .  .14; 

2.  The  "  Keeping  Powers "  of  a  Water  .'  .       19 

3.  The  Colour  Test            .             .  .  .20 

4.  Heisch's  Test    .              .             .  .  .    •   24 

5.  The  Zymotic  or  Microzyme  Test  .  .       25 


Xll  CONTENTS 

PAGE 

6.  The   Oxygen  or   Forchammer   Permanganate  of 

Potash  Process     .              .             .  .26 

A.  Qualitative  Examination    .             .  .26 

B.  Quantitative  Examination  .  .  .26 
Drs.  Letheby  and  Tidy's  Process  .  .28 
Drs.  Woods'  and  F.  de  Chaumont's  Process  33 
An  Improved  Process         .              .  .38 

7.  The  WanMyn,  Chapman,  and  Smith  Process  .       39 

8.  The  Frankland  and  Armstrong  Process  .  .53 

Table  exhibiting  different  classes  of  Waters      .       58 
A  Comparison  between  the  Residts  furnished  by 

the  three  last-named  Processes         .  .63 

Table  of  Comparison  .  .  .  .68 

Value  of  the  Frankland  and  Armstrong,  Wan- 
klyn,  Chapman,  and  Smith,  and  the  Quanti- 
tative Forchammer  Permanganate  of  Potash 
Processes  in  the  Detection  of  Dangerous 
Pollutions  .  .  .  .  .71 

9.  Koch's  Biological  Method  .  .  .74 
10.  The  Estimation  of  Dissolved  Oxygen       .  .       86 


CHAPTEE    III 

The  Determination  of  the  Mineral  Products  re- 
sulting FROM  Changes  in  the  Animal  Organic 
Matter         .  .  .  .  .  .91 

1.  Ammonia  .  .  .  .  .91 

2.  Nitrogen  as  Nitrates  and  Nitrites  .  .95 

A.  QuaKtative  Examination — the  Horsley  Test     106 

B.  Quantitative  Examination  .  .  .111 
Modification  of  Thorp's  Process       .             .114 


CONTENTS  XIU 

CHAPTEE   IV 

PAGE 

The  Determination  op  the  Amount  op  Solid  Resi- 
due, ITS  Appearance  Before,  During,  and  Apter 
Ignition,  and  the  Loss  op  Volatile  Matters 
thereby  occasioned  .  .  .  .124 

A.  The  Amount  of  Solid  Residue  or  Saline  Matters       124 

B.  The  Appearance  of  the  Solid  Residue  Before, 

Diu-ing,  and  After  Ignition      .  .  .128 

Table  of  Illustration  .  .  .130 

C.  The  Amount  of  Volatile  Matters  burnt  off  by 

Ignition  .  .  .  .  .132 

CHAPTEE    V 

The  Determination  op  the  Amount  op  Chlorine      .     135 

CHAPTEE    VI 

The  Determination  op  the  Hardness  .  .139 

CHAPTEE    VII 

The   Determination   op   the   Amount   op    Magnesia, 

Sulphates,  and  Phosphates  .  .  .144 

A.  Magnesia — Sulphate,  Carbonate,  and  Nitrate      .     145 

B.  Sulphates  of  Lime,  Magnesia,  and  Soda  as  An- 

hydrous Sulphiuric  Acid  .  .  .147 

C.  Phosphates       .  .  .  .  .150 

CHAPTEE    VIII 

The  Determination  of  Poisonous  Metals      .  -  .     154 


xiv  CONTENTS 


CHAPTEE    IX 

PAGE 

MiCEOscopic  Examination  of  a  Water  .  .161 


CHAPTEE    X 

The  Collection  of  Samples  of  Water  for  Analysis     170 

CHAPTEE    XI 

Time  occupied  in  performing  an  Analysis    .  .172 

CHAPTEE   XII 

Entry  of  Analysis  in  Note  and  Record  Books        .     175 

CHAPTEE    XIII 

Mistakes   of  Water  Analysts,  and   how   to   avoid 

THEM  ......       177 

CHAPTEE    XIV 

Useful  Memoranda  for  Medical  Officers  op  Health 

WHEN    performing-    WaTER    ANALYSIS  .  .185 

CHAPTEE    XY 

Formation  of  Opinion  and  Preparation  of  Report 

AS  TO  Sample  of  Water  submitted  to  Analysis  .     188 


CONTENTS  XV 

PAGE 

A.  Summary  of  Data  on  which  to  base  an  Opinion  .     195 

B.  Valuation  Tables  and  District  Standards  .     196 

C.  Diagnosis  and  Formation  of  an  Opinion  .  200 
Diagnosis  of  a  Peaty  Water  .  .  .205 
Diagnosis  of  Pollution  by  Urine,  or  by  Slop  and 

Sink  Water  .  .  .  .209 

Diagnosis  of  Pollution  by  contents  of  Cesspools 

and  Sewers  .  .  .  .210 

D.  Preparation  of  Report  .  .  .  .212 


CHAPTER    XVI 

Concluding  Eemarks  on  Section  I.    .  .  .215 

Recipes  op  Standard  Solutions,  etc.  .  .216 


SECTION   II.— SANITAEY   EXAMINATION 
OF  AIE 

CHAPTER    XYII 

PAGE 

The  Pueity  of  Aie       .  .  .  .  .221 

PART    I 

Different  Kinds  op  Impurities  .  .  .231 

CHAPTER    XYIII 

Organic  Matter  .  .  .  .  .232 


XVI  CONTENTS 


CHAPTEE    XIX 

PAGE 

Oxides  of  Caebon          .  .  .  .  .240 

A.  Carbonic  Acid  .....     240 

B.  Carbonic  Oxide  .  .  .  .247 


CHAPTEE    XX 

Putrefactive    Processes,    Sewage    Emanations,    and 

EXCREMENTAL    FiLTH  ....       254 


CHAPTEE    XXI 

Poisonous  Gases  and  Injurious  Vapours       .  .257 

CHAPTEE    XXII 

Suspended    Animal,    Vegetable,    and    Metallic,    as 

WELL  AS  Mineral  Impurities  .  .  .     258 

CHAPTEE    XXIII 

Emanations  from  Ground  having  Damp  and  Pilthy 
Subsoil — Subsoil  Air,  Churchyard  Air,  Marsh 
Air    .  .  .  .  .  .  .     264 

CHAPTEE    XXIV 

The  Deleterious  Effects  on  Health  of  the  Air  of 

our  Houses  ......     270 


CONTENTS  XVll 


PAET    II 

PAGE 


The  Detection  and  Estimation  of  the  Amount  of 
THE  most  Important  Impurities  found  in  the 
Air    .  .  .  .  .  .  .291 


DIRECT  METHOD 


CHAPTEE    XXV 

Modes  of  Observing  Solid  Bodies  in  the  Air,  and 

OF  Separating  them  for  Examination      .  .292 


CHAPTEE    XXVI 

Microscopical  Examination  of  the  Dust  of  the  Air     301 

CHAPTEE    XXVII 

The  Chemical  Examination  of  Air    .  .  .310 

A.  Organic  Matter  .  .  .  .     312 

B.  Carbonic  Acid  .  .  .  ,  .328 

CHAPTEE    XXVIII 

The  Biological  Examination  of  Air  .  .  .     340 

CHAPTEE    XXIX 

Metallic  Poisons  : — Arsenic,  Copper,  and  Lead        .     343 

& 


XVIU  CONTENTS 


INDIRECT  METHOD 


CHAP TEE    XXX 

PAGE 

Estimation  of  Ozone  and  other  Aie  Purifiers         .     349 


PAET    III 

Sketch  of  Relation  between  certain  Meteorolo- 
gical Variations  in  the  Condition  op  the  Air, 
and  states  of  health  and  disease  .  .358 

CHAPTEK    XXXI 

1. — The  Influence  of  Differences  of  Temperature, 
Solar  Radiation,  Moisture,  and  Barometric 
Pressure  of  the  Air,  Direction  of  the  Wind, 
etc.,  on  Health       .....     362 

A.  The  Temperature  of  the  Air  =  Air  Warmth         .     362 

B.  The  Solar  Radiation      ....     367 

C.  The  Hygrometric  State  of  the  Air  .  .     369 

D.  The  Pressure  of  the  Air  .  .  .374 

E.  The  Direction  of  the  Wind        .  .  .378 


CHAPTEE    XXXII 

-The  Meteorological  Conditions  which  appear 
to  favour  or  retard  the  development  of  cer- 
TAIN Diseases  .....      380 

1.  Siu:gical  Fever  after  Operations  .  .  .381 

2.  Smallpox  .  .  .  .  .383 


CONTENTS 

XIX 

PAGE 

3.  Measles             .... 

384 

4.  Whooping-Cough 

386 

5.   Scarlet  Fever    .... 

387 

6.  Fever  ..... 

389 

7.  DiarrhcBa,  Dysentery,  and  Cholera 

391 

8.   Bronchitis,  Pneumonia,  and  Asthma 

396 

9.   Phthisis  Pulmonalis 

398 

10.  Diphtheria        .... 

398 

11.  Hydrophobia     .... 

399 

12.   Erysipelas  and  Puerperal  Fever 

399 

13.  Insanity            .... 

400 

14.  Eheumatism      .... 

401 

Mortality  at  Different  Ages  and  of  each  Sex      .            402-405 

PAET    IV 

Mode  of  Observing  the  Meteorological  States  and 

Variations  in  the  Condition  of  the  Air  .     406 


CHAPTEE    XXXIII 

1. — The  Atmospheric  Pressure 


407 


CHAPTEE    XXXIV 

2. — The  Temperature  of  the  Air 


411 


CHAPTEE    XXXV 

3. — The  Hygrometric  Condition  op  the  Air 


422 


XX  CONTENTS 


CHAPTEK    XXXVI 


PAGE 


4. — The  Dikection  and  Strength  of  the  Wind         .     430 


CHAPTEE    XXXVII 

5. — The  Electrical  State  of  the  Air  .  .     434 

Kegistration  of  Meteorological  Observations       .  .     439 


SECTION  III.— SANITAEY  EXAMINATION 
OF  FOOD 

CHAPTEE    XXXVIII 


PAGE 


The  Purity  of  Food  .  .  .  .  .     443 


CHAPTEE    XXXIX 

Inspection   and    Examination    of    any    Animal    in- 
tended FOR  THE  Food  of  Man        .  .  .     446 


CHAPTEE    XL 

Inspection  and  Examination  op  Carcases  op  Ani- 
mals, Meat  and  Flesh  Exposed  for  Sale,  or 
Deposited  for  the  Purpose  of  Sale,  or  of  Pre- 
paration for  Sale,  and  intended  for  the  Food 
OF  Man         .  .  .  .  .  .449 


CONTENTS  XXI 

PAGE 

Characters  of  Good  and  Bad  Meat        .  .  .     450 

The  Prevalent  Diseases  of  Stock  in  relation  to  the 

Supply  of  Meat  for  Human  Food    .  .  .454 

1.  Contagious  Fevers    .  .  .  .454 

2.  Anthracic  and  Anthracoid  Diseases,  etc.  .  458 
Arguments  against  the  Employment  of  Diseased  Meat  .  463 
Arguments  in  favour  of  the  Employment  of  Diseased 

Meat         .  .  .  .  .  .464 

3.  Parasitic  Diseases  ....  468 
Immature  Veal  and  Lamb  .  •.  .  .476 
Poisonous  Pork,  Ham,  Sausages,  etc.     .              .             .477 


CHAPTEE    XLI 

Ihspection  and  Examination  of  Poultey,  Game,  etc.     478 

CHAPTEE    XLII 

Inspection  and  Examination  of  Fish  .  .     480 

CHAPTEE    XLIII 

Meat  of  Poisoned  Animals      .      •       •  •  •     482 

CHAPTEE    XLIV 

Destruction  op  Condemned  Flesh       .  .  .     484 

CHAPTEE    XLV 


Inspection   and   Examination   of    Fruit   and    Vege- 
tables ...... 


486 


XXll  CONTENTS 

CHAPTEE    XLVI 

PAGE 

Turned  Provisions         .....     488 

CHAPTEE    XLVII 

Inspection  and  Examination  of  Corn            .  .     489 

CHAPTEE    XLVIII 

Inspection  and  Examination  op  Flour          .  .493 

Chemical  Examination              .              .              .  .     495 

MicroscoiDic  Examination          .             .              .  .499 

CHAPTEE    XLIX 

Inspection  and  Examination  of  Bread           .  .508 

Microscopic  Examination          ,              .             .  .509 

Adulterations  of  Bread              .              .              .  .509 

Chemical  Examination              .              .             .  .513 

CHAPTEE    L 

Inspection  and  Examination  op  Milk             .  .     520 

Microscoi^ic  Appearance             .             .             .  .522 

Physical  Pecnliarities  .              .             .             .  .523 

Chemical  Examination               .             .             .  .525 

Milk  supplied  by,  and  tainted  by,  Diseased  Animals  .     535 
Milk  contaminated  by  water  polluted  with  Organic 

Impurities              .              .              .              .  .544 


CONTENTS  xxiii 


APPENDIX 

PAGE 

Distilled  Water  and  Chemicals  .  .              .     547 

List  of  AiDparatus  requisite       .  .  .             .548 

Rules  for  Interchange  of  Different  Expressions  of  Results 

of  Analysis            .             .  .  .             .550 
Rules   for  Conversion  of  Degrees  of  Scales  of  Ther- 
mometers               .              .  .  .              .551 
Metrical  Weights  and  Measures  .  .             .551 


Index      .......     553 


INTEODUCTORY  OBSERVATIONS 


The  elementary  principles  on  which  the  greater  part  of 
the  work  of  the  Medical  OSicer  of  Health  is  based^  may 
be  truly  said  to  be  the  prevention  of  the  pollution  of 
Water  and  of  Air  with  filth  and  its  products,  and  the 
prevention  of  the  consumption  of  articles  of  Food  deleteri- 
ous to  health. 

Pure  Water,  pure  Air,  and  good,  wholesome,  unadul- 
terated Food  constitute  the  pillars  which  form  the  trijDod 
on  which  rests  the  "  mens  sana  in  corpore  sano." 

My  ideal  of  a  Medical  Officer  of  Health  is  that  of  a 
physician  who  is  thoroughly  conversant  with  every  ques- 
tion affecting  Public  Health,  and  who  is  able  to  analyze 
quantitatively  water,  air,  and  food ;  and  is  so  well  versed 
in  analytical  work  as  to  be  able  to  take  his  oath  in  a 
court  of  justice  respecting  any  matter  requiring  the 
assistance  of  a  scientific  expert  in  state  medicine.  Such 
a  man  should  be  debarred  from  private  practice,  and 
placed  over  a  large  area  with  definite  boundaries,  such  as 
a  county  or  riding.  His  appointment  should  be  perma- 
nent, so  that  he  may  fearlessly  and  conscientiously  per- 
form his  duty.  Every  medical  practitioner  in  his  district 
should  act  towards  him  in  the  capacity  of  an  assistant. 
The  Medical  Officer  of  Health  should  in  fact  be  the  Head 
Centre  of  all  Public  Health  affairs  in  each  county. 

B 


2  INTRODUCTORY  OBSERVATIONS 

First,  as  to  Water. — The  examination  of  drinking 
waters  forms  a  very  important  portion  of  the  duty  of 
those  who  engage  in  a  crusade  against  preventable  disease. 
A  health  officer  should  not  only  be  prepared  to  answer 
such  a  question  as,  "Does  a  w^ater  contain  a  deleterious 
amount  of  organic  matter  ?"  but  should  be  able  to  reply 
to  such  interrogations  as,  "  Is  this  water  wholesome  and 
good?"  "Which  of  several  specified  wells  furnishes  the 
purest  water  ?"  etc. 

Some  are  disposed  to  think  that  it  is  unadvisable  for 
a  Medical  Officer  of  Health  to  analyze  water.  The  list 
of  his  duties,  as  laid  down  by  the  Local  Government 
Board,  certainly  contains  no  order  that  he  should  act  as 
a  water  analyst.  The  latest  Adulteration  Acts  (Food  and 
Drugs  Act  of  1875,  and  the  Amended  Act  of  1879) 
expressly  excludes  water  from  its  provisions.  Few,  I 
should  presume,  would  hold  that  water  is  not  in  some 
sense  a  food  (much  more  so  than  either  mustard  or 
pickles) ;  and  that,  having  regard  to  the  derivation  of  the 
word  "adulterate,"  the  sewage  and  water  supplied  by 
some  wells  could  not  strictly  be  considered  to  be  "a 
change  to  another  "  (the  exact  meaning  of  the  word)  of  an 
article  of  daily  consumption,  of  a  very  serious  character. 

A  Medical  Officer  of  Health  who  can  promptly  give 
an  authoritative  opinion  as  to  the  quality  of  a  water  is 
much  more  helpful  to  the  Sanitary  Authorities  with  which 
he  may  be  connected,  than  one  wdio  is  unable  so  to  do. 
Continually  cases  arise,  in  the  working  of  a  large  district, 
where  a  Sanitary  Authority  requires  an  immediate  deci- 
sion as  to  the  quahty  of  a  water,  in  order  that  steps  may 
be  taken  with  the  least  possible  delay  in  the  prevention 
of  the  extension  of  a  disease.  If,  as  is  customary  in  some 
places,  samples  of  water  are  sent  to  professional  analysts 
living  at  a  distance,  great  loss  of  time  is  generally  experi- 
enced, and  the  analyses  of  waters  yield  illusory  results 


INTRODUCTORY  OBSERVATIONS  6 

in  consequence  of  being  examined  in  a  stale  instead  of  in 
a  fresh  condition.  I  Imxe  often  known  a  month  or  more 
to  elapse  before  the  report  is  received,  when,  frequently, 
the  opportunity  for  acting  on  the  opinion  expressed  has 
passed  away.  Moreover,  a  Medical  Officer  of  Health 
requires,  for  his  own  guidance  in  tracing  out  the  causes 
of  diseases,  and  in  taking  measures  to  stop  their  spread, 
to  ascertain  expeditiously  and  with  precision  the  state  of 
waters. 

Secondly,  as  to  Air. — What  can  be  more  important 
than  the  establishment  of  some  rules  of  practice  as  to  the 
purity  of  the  air  of  our  houses  and  public  buildings  ? 
There  can  be  no  question  but  that  there  is  a  distinct 
causative  relation  between  consumption  and  re-breathed 
air,  between  the  condition  of  the  air  in  unventilated  and 
crowded  dwellings  and  the  prevalence  of  lung  affections. 
An  enormous  field  is  afforded  to  the  health  officer  in  the 
study  of  the  subject  of  the  defilement  of  the  air  by 
metallic,  mineral,  and  other  visible  impurities,  with  a  %dew 
to  the  discovery  of  some  means  whereby  the  condition 
of  those  classes  who  have  to  earn  their  daily  bread  by 
working  at  such  unwholesome  avocations  as  button 
manufacture,  stone  masonry,  the  cotton,  wool,  and  silk 
industries,  etc.,  may  be  ameliorated. 

Thirdly,  as  to  Food. — The  attention  of  the  Medical 
Officer  of  Health  should  undoubtedly  be  restricted  in  his 
analytical  examinations  to  the  necessaries  of  life,  and  to 
those  substances  that  are  apt  to  be  injurious  in  them- 
selves, or  are  liable  to  be  adulterated  with  substances 
deleterious  to  health.  Professional  analysts,  distinct 
from  Medical  Officers  of  Health,  there  always  must  be. 
On  these  officials  devolves  the  duty  of  analysing  foods, 
etc.,  which  contain  fraudulent  but  harmless  admixtures, 
such,  for  example,  as  the  compound  of  mustard,  and  of 
cocoa,  with  starch — an   innocuous  diluent,  the   mixture 


4  INTRODUCTORY  OBSERVATIONS 

of  sardines  and  sprats  with  anchovies,  and  of  salt  with 
gelatine  to  increase  its  weight  in  the  scales,  etc. 

The  duties  of  the  Medical  Officer  of  Health,  as  laid 
down  by  the  Legislature,  all  rest  on  the  assumption  that 
he  is  the  judge  on  all  subjects  relating  to  iniUic  health.  It 
is  of  course  difficult  to  draw  a  hard  and  fast  line  in  this 
matter,  as  in  every  other  in  this  world. 

"  1st  Duty. — He  shall  inform  himself,  as  far  as  prac- 
ticable, respecting  all  influences  affecting  or  threatening 
to  affect  injuriously  the  public  health  within  the  district. 

"  2cl  Duty. — He  shall  inquire  into,  and  ascertain  by 
such  means  as  are  at  his  disposal,  the  causes,  origm,  and 
distribution  of  diseases  within  the  district,  and  ascertain 
to  what  extent  the  same  have  depended  on  conditions 
capable  of  removal  or  mitigation. 

"  3cZ  Duty. — He  shall,  by  inspection  of  the  district, 
both  systematically  at  certain  periods,  and  at  intervals  as 
occasion  may  require,  keep  himself  informed  of  the  con- 
ditions injurious  to  health  existing  therein. 

"  Wi  Duty. — In  any  case  in  which  it  may  appear  to 
Mm  to  be  necessary  or  advisable,  or  in  which  he  shall  be 
so  directed  by  the  Sanitary  Authority,  he  shall  himself 
inspect  and  examine  any  animal,  carcase,  meat,  poultry, 
game,  flesh,  fish,  fruit,  vegetables,  corn,  bread,  or  flour, 
exposed  for  sale,  or  deposited  for  the  purpose  of  sale,  or 
of  preparation  for  sale,  and  intended  for  the  food  of  man, 
which  is  deemed  to  be  diseased,  or  unsound,  or  unwhole- 
some, or  unfi.t  for  the  food  of  man ;  and  if  he  finds  that 
such  animal  or  article  is  diseased,  or  unsound,  or  unwhole- 
some, or  unfit  for  the  food  of  man,  he  shall  give  such 
directions  as  may  be  necessary  for  causing  the  same  to  be 
seized,  taken,  and  carried  away,  in  order  to  be  dealt  with 
by  a  justice,  according  to  the  pro"\dsions  of  the  statutes 
applicable  to  the  case." 

The   First  Duty   alone   is    comprehensive  enough   to 


INTEODUCTOEY  OBSEEVATIONS  5 

include  the  consideration  of  each  of  the  three  subjects 
treated  of  in  the  following  pages,  and  even  more.  As 
Medical  Officers  of  Health  are  often  at  present  inundated 
with  analytical  work  by  those  who  are  simply  curious  as 
to  whether  their  drinking  water  is  or  is  not  good,  or  as 
to  the  reason  why  it  does  not  make  good  tea,  or  as  to 
why  their  sugar  turns  their  tea  of  a  black  colour,  or  as 
to  whether  their  wall-papers  contain  arsenic,  or  as  to 
why  their  brandy  and  water  assumes  sometimes  an  inky 
hue,  it  is  a  great  protection  to  the  Medical  Officer  of 
Health  if  he  refers  all  applicants  to  the  Sanitary  Author- 
ity of  the  district  for  an  order,  with  the  previous  under- 
standing, arrived  at  with  the  Sanitary  Authority,  that  it 
will  not  give  him  any  instructions  to  analyze  at  the 
public  expense,  unless  evidence  is  placed  before  it  of  a 
nature  calculated  to  show  that  the  substance  respecting 
which  the  request  is  made  has  been  or  is  likely  to  be 
deleterious  to  health,  and  that  the  applicant  cannot  afford 
to  pay  for  the  analysis  out  of  his  or  her  own  pocket. 

As  all  chemical  examinations  to  be  exact  must  be 
quantitative,  and  as  all  inaccurate  examinations  are  of 
little  worth,  and  as,  moreover,  the  quantitative  analysis 
of  a  substance  is  not  laid  down  as  one  of  the  duties  of  a 
Medical  Officer  of  Health  by  the  Government,  it  follows  as 
a  matter  of  logical  sequence,  that  all  quantitative  analy- 
tical work  conducted  for  a  Sanitary  Authority  and  for  the 
public  should  be  paid  for.  Work  performed  gratuitously 
is  rarely  valued. 

The  progress  of  a  knowledge  of  Preventive  Medicine 
is  exceedingly  slow.  The  Medical  Officer  of  Health,  who 
is  the  schoolmaster  of  his  district  as  to  sanitary  matters, 
must  necessarily  find  his  work  of  a  very  uphill  character. 
He  is  continually  regarded  as  an  irreverent  individual,  who 
is  wicked  enough  to  interfere  with  the  purposes  and 
designs  of  the  Almighty.     Thousands  are  still  to  be  found 


6  INTEODUCTOKY  OBSERVATIONS 

who  believe  that  if  a  water  is  bright  and  clear,  and  not 
unpleasant  to  the  taste,  it  must  be  good;  whilst  it  has 
been  proved,  over  and  over  again,  that  such  a  water  may 
be  polluted  with  unspeakable  filth,  and  that  an  excessive 
brilliancy  of  a  water  is  a  suspicious  sign. 

There  can  be  no  question,  however,  but  that  the  ele- 
ments of  sanitary  science  are  slowly  and  surely  influ- 
encing the  people  of  this  and  of  other  countries  for  good. 
Such  cases  as  that  of  the  servant  who,  coming  from  an 
obscure  village  near  the  Dartmoor,  objected  to  the  pure 
water  of  a  distant  town  where  she  was  in  service,  on  the 
ground  of  its  being  devoid  of  either  taste  or  smell,  are 
becoming  rare. 


SECTION  I 


SANITAEY  EXAMINATION 


OF  A 


DRINKING  WATER 


CHAPTEE    1 

THE    WHOLESOilEXESS    OF    A    WATEK 

PuEE  spring  waters,  devoid  of  all  metallic  impurities,  are 
undoubtedly  the  most  wholesome  waters  for  drinking 
purposes.  Pure  shallow  and  artesian  well  waters  occupy 
a  second  place.  The  sahne  waters  furnished  by  some 
artesian  wells,  and  the  rain  that  descends  in  the  country 
far  away  from  towns  and  cities,  occupy  jointly  a  third 
position  in  order  of  merit ;  and  lastly  come  the  waters 
of  streams  and  rivulets,  the  majority  of  which  contain 
more  or  less  filth,  and  in  times  of  hesivj  rains,  soil  and 
mineral  debris  of  every  description.  All  will  readily 
understand  the  reason  that  spring  water  should  be  placed 
first,  and  river  water  last  in  the  order  of  wholesomeness, 
but  the  motive  for  assigning  to  highly  saline  artesian 
well  water  and  rain  water  a  situation  inferior  to  both 
spring,  shallow  and  deep  well  waters  is  perhaps  not  so 
obvious.  Artesian  well  waters  frequently  contain  an 
excess  of  saline  matters  (vick  page  127).  Eain  water 
possesses  an  infinitesimal  amount  of  saline  substances,  and 
is  almost  entirely  devoid  of  lime — a  substance  which 
is  so  important  in  building  up  the  bony  tissues  of  young 
animals.  I  am  aware  that  some  few  eminent  men  think 
that  young  creatures  solely  derive  the  lime  which  they 
require  from  their  food-^  (vide,  for  example,  the  CAidence 

^  One  pound  of  flour  contains  only  IJ  grain  of  lime,  and  that  in  a 
form  which  is  associated  with  the  more  insoluble  part  of  the  grain. 


10 


THE    WHOLESOMENESS    OF    A   WATER 


of  Dr.  Lyon  Playfair  in  the  Sixth  Eeport  of  the  Eivers 
Pollution  Commissioners,  page  189).  Those  who  entertain 
this  view  consider,  I  believe,  that  water  simply  acts  as  a 
diluent  or  solvent  in  nutrition.  I  have  no  room  here  to 
combat  this  opinion,  but  can  simply  give  it  as  my  own 
that  the  young  animal  supplies  the  wants  of  its  system 
for  lime  from  every  available  source.  Many  towns  in 
England  and  Scotland  are  supplied  by  waters  collected 
from  the  surface  of  uncultivated  land  in  lakes  and 
reservoirs.  These  "  upland  surface  waters "  are  often 
insufficiently  aerated,  and  contain  an  excess  of  peaty  and 
other  vegetable  matter  which  renders  them  unpalatable, 
and  sometimes  gives  them  a  slightly  bitter  taste.  In 
consequence  of  their  softness,  however,  they  are  very 
useful  for  domestic  and  manufacturing  purposes. 

It  is  almost  impossible  to  define  a  wholesome  water ; 
but  here  are  two  examples  of  most  wholesome  spring 
waters : — 


Name  and  Description  of 
tlie  Sample  of  Water. 

Grains 

per  Gallon. 

Part  per  Million 

=  Milligramme 

per  Litre. 

Total 
Hard- 
ness. 

-o 

a 

|1 

igen 
rates 
d 
ites. 

Albumi- 
noid 
Ammonia. 

Spring  supplying  vil- 

o 

^1 

< 

P 

lage    of   Woodham 

Walter,  Essex 

21- 

2-4 

•02 

nil. 

•00 

•01 

6 

Spring    near     Drew- 

steignton,        Dart- 

moor, Devon 

14- 

1-6 

•03 

nil. 

•02 

•01 

8 

N.B.— No  metals  in  either 

water. 

It  may  be  useful  to  give  examples  of  the  composition 
of  good  shallow  well  and  good  artesian  well  waters  and 
pure  rain  water : — 


THE    WHOLESOMENESS    OF    A   WATER 


11 


Part  per  Million 

Total 

Name  and  Description  of 
the  Sample  of  water. 

Grains  per  Gallon. 

=  Milligramme 
per  Litre. 

Hard- 
ness. 

3 

itrogen 
titrates 
and 
i trites. 

.4,     g 

III 

Ed 

Good     shallow     well 

012 

°^ 

^c»        » 

p 
< 

^    ^ 

P 

water.      Depth   25 

feet 

30- 

7- 

•01 

•2 

•01 

•05 

13 

Good    Artesian    well 

water.     Depth  300 

feet 

85-4 

27-1 

•02 

nil. 

•74 

■03 

5 

Good    Artesian    well 

water.     Depth  175 
feet 

lOG-4 

37-7 

•04 

nil.    y 

ti^si 

^ 

Pure   rain   water   col- 

if. 

lected      in      open 

Jr  LtBRj 

i.'R^ 

country- 

1- 

•6 

•01 

nil.V, 

•45 

^0^"' 

»^Mpj   . 

Shallow 
well  water. 


Artesian 
well  water. 


Rain  tfater. 


:4<r/ 


^10N^,a^ 


In  forming  an  opinion  as  to  the  que 
for  sanitary  purposes,  tlie  old-fashioned  plan  of  cafemlly 
estimating  the  number  of  grains  per  gallon  of  each  saline 
constituent,  often  8  or  10,  and  at  times  as  many  as  18  or 
19  in  number,  is  perfectly  unnecessary.  Of  what  im- 
portance is  it  to  ascertain  the  exact  fraction  of  a  grain  of 
silica  or  alumina  which  a  water  may  contain,  or  whether 
it  does  or  does  not  possess  a  trace  of  fluorine  ?  It  is  of 
not  the  slightest  practical  moment  as  to  whether  our 
drinking  water  contains  3  or  6  grains  of  carbonate  of 
lime  per  gallon,  or  whether  1  or  5  grains  of  chloride  of 
sodium  are  dissolved  in  the  same  quantity,  provided  it  is 
pure.  In  the  case  of  mineral  waters,  and  of  waters  pro- 
posed to  be  used  for  brewing  and  other  commercial  pur- 
poses, a  detailed  analysis,  containing  the  exact  amount  of 
every  salt,  may  sometimes  be  required. 

Equally  useless  for  all  sanitary  work  is  the  estimation 
of  the  number  in  cubic  inches  of  the  nitrogen,  oxygen, 
and  carbonic  acid  gases  evolved  on  boiling  a  water,  and 
the  determination  of  the  temperature  of  a  water. 

In    forming    a    judgment    as    to    the    character     of 
a    water,    it    is    desirable   for    the    Medical    Officer    of 


■based. 


12  THE    WHOLESOMEXESS    OF    A    WATER 

Health    to    ascertain     some     or     all     of    the    following 
particulars : — 
Data  on  (fj)    The  amount  and  nature  of  the   organic  matter, 

opinion  whether  animal  or  vegetable. 

.^°pri'^  ^'^  (^)   •^■^^^  existence  or  not  of  the  products  of  the  oxida- 

tion of  organic  matter,  such  as  the  nitrates  and 
nitrites,  and  in  certain  cases  the  quantity  of 
these  salts. 

(c)  The  amount  and  nature  of  the  saline  constituents. 

(d)  The  degree  of  hardness. 

(e)  The   existence    and    the    amount,    if   present,  of 
metals. 

(/)  The  existence  and  the  amount  of  purgative  salts, 
such  as  the  sulphate  and  carhonate  of  magnesia, 
or  the  sulphates  of  soda  and  potash. 
In  the  majority  of  cases  that  present  themselves,  in- 
formation on  the  first  two  points  is  alone  needed. 


CHAPTEE  II 

THE  DETEEMINATION  OF  THE  AMOUNT  AXD  NATUEE  OF 
THE  OEGANIC  MATTER 

All  waters,  even  the  purest,  contain  some  organic  matter. 
The  excess  is  alone  oljjected  to ;  and  especially  that  of 
animal  origin,  which  is  especially  prone  to  pass  through 
certain  putrefactive  changes. 

iSTo  process  has  as  yet  been  discovered  for  estimating 
the  absolute  amount  of  organic  matter  present  in  a  water. 
The  best  modes  of  analysis  furnish  us  only  with  ap- 
proximations, more  or  less  correct,  to  the  exact  quantity. 

A  great  variety  of  methods  have  been  employed  at 
different  times  by  English  and  German  chemists.  With- 
out adverting  to  the  history  of  the  subject,  which  would 
be  foreign  to  the  purpose  of  this  little  work,  I  shall 
describe  those  w^hich  have  taken  the  lead  and  are  now 
believed  in  and  practised  by  medical  of&cers  of  health 
and  analysts  in  their  attempts  to  pronounce  on  the 
quality  of  a  water.  The  employment  of  these  very 
dissimilar  modes  has  led,  unfortunately,  to  most  contra- 
dictory results  : — 

1.  The  odour  of  a  water.  siostpopu- 

2.  The  "  keeping  powers  "  of  a  water.  processes. 

3.  The  colour  test. 

4.  Heisch's  test. 

5.  The  zymotic  or  microzyme  test. 

6.  The  oxygen  or  Eorchammer  permanganate  of 
potash  process. 


14  THE    DETEEMINATION    OF    THE    AlVIOUNT    AND 

7.  The  Wanklyn,  Chapman,  and  Smith  process. 

8.  The  Frankland  and  Armstrong  process. 

9.  Koch's  biological  method. 

10.  The  estimation  of  dissolved  oxygen. 

1.  The  Smell  of  a  Watek. 
The  most  rough- and-readyway  that  has  been  employed  for 
ascertaining  whether  or  not  a  water  is  polluted  with  organic 
matter  is  to  partly  fill  a  clean  bottle  with  a  sample  of  it,  and, 
having  violently  shaken  the  same,  to  take  a  hearty  sniff  at 
the  air  of  the  bottle  which  has  been  agitated  with  the  water. 
If  the  air  smells  sweet  and  fresh,  the  absence  of  an  injurious 
amount  of  organic  matter  is  inferred,  and  vice  versd.  There 
is  no  doubt  but  that  much  may  be  learnt  in  this  way  by  those 
who  do  not  blunt  their  sense  of  smell  by  smoking,  especially 
if  they  frequently  practise  this  primitive  test.  It  is  very 
easy  to  distinguish  thus  between  river  and  spring  water ; 
and  a  very  impure  water,  which  may  exhibit  no  fault  to 
the  eye,  may  frequently  disclose  to  the  olfactory  nerves  the 
fact  of  its  pollution.  There  is  sometimes  great  difficulty 
in  distinguishing  between  a  water  rendered  offensive  by 
decomposing  starch  in  any  form,  e.g.  rotten  turnips,  and 
one  polluted  by  the  presence  of  a  dead  animal,  e.g.  a 
rabbit,  bird,  or  rat.  If  no  smell  is  noticed  in  the  manner 
described,  some  may  be  observed  on  gently  warming  the 
water ;  and  if  none  then,  the  addition  of  a  few  grains 
of  caustic  potash  may  render  it  apparent.  Prof.  Ira 
Eemsen  states  (Eeport  on  the  Impurity  of  the  Water 
Supply  of  Boston,  U.S.,  1881)  that  the  best  way  of 
detecting  the  cucumber  odour  in  any  water  but  slightly 
affected,  is  to  pass  about  a  pint  of  it  through  a  paper 
filter  which  will  reveal  it,  although  it  may  be  quite 
impossible  to  discover  it  by  warming  the  water.  Mr. 
Crookes'  device  is  as  follows : — "  Take  two  or  three 
ounces  of  the  water,  the  smell  of  which  is  to  be  tested. 


NATURE  OF  THE  ORGANIC  MATTER         15 

and  warm  it  carefully  and  quickly  in  a  flask  to  a 
temperature  of  about  102°  or  104°  F,,  say  4°  or  6° 
above  blood  heat ;  then  take  a  glass  tube  of  about  -|  inch 
diameter  and  3  feet  long,  put  the  flask  containing  the 
water  on  the  floor,  carefully  suck  up  the  water  five  or 
six  times  into  this  tube  until  the  inside  of  the  tube  is 
thoroughly  wetted  with  the  water,  then  allow  the  water 
to  escape,  and  closing  one  nostril  with  the  finger,  take 
two  or  three  full  inspirations  through  the  tube  with  the 
other  nostril."  It  should  be  borne  in  mind,  however, 
that  the  existence  of  an  unpleasant  odour  or  taste  about 
the  water  from  a  well  sunk  in  clay  is  no  proof  of  the 
pollution  of  that  water  with  organic  matter.  Water,  if 
allowed  to  remain  long  in  contact  with  certain  kinds  of 
clay,  in  some  situations,  acquires  such  an  objectionable 
smell  as  to  be  sometimes  quite  undrinkable,  and  yet 
may  not,  at  the  same  time,  contain  an  amount  of  organic 
matter  that  would  warrant  its  condemnation.  Com- 
plaints are  made  sometimes  of  this  smell  in  the  case  of 
waters  of  artesian  wells  sunk  through  the  clay,  where 
the  supply  of  water  is  much  greater  than  the  demand. 
A  well  of  this  kind  can  be  made  to  furnish  excellent 
water  by  the  frequent  withdrawal  of  its  contents,  or,  if 
that  is  not  practicable,  and  the  well  be  an  artesian  one, 
by  the  filling  up  of  the  dug  portion  of  the  well  and  by 
drawing  the  supply  solely  from  the  bore-pipe.  In  this 
way  the  water  is  prevented  fi'om  lying  long  in  contact 
with  the  sides  of  the  well.  The  clay  contains  in  some 
situations  little  nodules  of  iron  pyrites — i.e.  sulphide 
of  iron,  and  fossils  of  the  same  composition.  They 
possess  a  peculiar  odour,  which  they  give  forth,  espe- 
cially when  wetted  and  rubbed.  This  odour  seems  to 
be  in  some  cases  communicated  to  the  water,  and  re- 
minds one  of  sulphurous  acid,  and  occasionally  of  fennel. 
These  offensive  waters  often  contain  such  an  enormous 


'  waters. 


16  THE    DETEKMINATION    OF    THE    AMOUNT    AND 

"  Brackish "  excess  of  clilorides  and  other  saline  matters  as  to  be  not 
potable ;  they  are  known  by  the  public  as  "  brackish " 
waters.     Here  is  an  example  : —  gra.xs  pek  gallon. 

Solids.  Chlorine. 

Well  behind  "Compasses,"  PH.  WH    .         .         380-  29-5 

'Eotten      Other   waters    from   the   clay  have   a   decided   smell   of 

era-      TMiifo-m  ^  ^ 

sulphuretted  hydrogen  gas,  and  become  turbid  on  stand- 
ing, in  consequence  of  the  separation  of  sulphur.  Books 
tell  us  that  sulphuretted  hydrogen  is  generated  from 
the  decomposition  of  water  and  iron  pyrites.  Before 
this  gas  is  produced,  I  think  with  Mr.  Slater  that  a 
partial  decomposition  of  sulphide  of  iron  probably  occurs 
with  a  formation  by  oxidation  of  sulphuric  acid.  This 
acid  acts,  then,  on  the  remaining  sulphide  of  iron, 
evolving  sulphuretted  hydrogen  gas. 

It  has  been  considered  probable  by  some  that  this  gas 
arises  from  the  decomposition  of  sulphates  through  the 
instrumentality  of  certain  algse. 

Prof  Kubel  states  -^  that  if  water  is  warmed  to  110° 
F.,  coal  gas  if  present  in  a  water  may  be  detected  by  the 
sense  of  smell,  when  chemical  means  fail  to  do  so. 

The  waters  from  wells  in  towns  and  villages  sometimes 
contain  carbolic  acid  and  paraffin  or  benzoline  which  has 
soaked  into  the  soil  from  leaky  cesspools  ^  or  vessels.^ 
The  odour  of  carbolic  acid  is  easily  recognizable,  but  that 
of  paraffin  resembles,  if  it  is  in  small  quantity,  gas,  and 
the  emanations  from  drains.  The  water  from  a  well  at 
Fryerning,  Essex,  described  as  extra  pure  was  found  by 
me  to  possess  a  suspicious  smell  of  paraffin  which  disap- 
peared on  warming.  The  employment  of  Mr.  Crookes' 
device  did  not  increase  its  perceptibility.      On  allowing 

^  Anleitung  zur  Untersuclmng  von  Wasser.     Zweite  Auflage  von  Dr. 
F.  Tiemann  :  Braunschweig,  1874. 

2  Fallacies  of  Empirical  Standards  in  Water  Analysis,  by  Dr.  Ashby. 

3  Vide  Dr.  Gilbert  Child's  Keport  for  1874,  on  the  Sanitary  Condition 
of  the  Combined  Districts  in  Oxfordshire. 


NATUKE  OF  THE  ORGANIC  MATTER 


17 


the  deposit  to  settle,  it  was  found  on  microscopic  exami- 
nation to  be  separated  here  and  there  by  wavy  lines  of 
an  intensely  black  colour,  surrounded  by  a  brownish 
coating  (of  a  resinous  appearance)  evidently  produced  by 
the  solvent  action  of  the  water  on  the  black  matter. 

Peculiar  odours  and  tastes  have  been  observed  in  some  Fish-iike 
of  the  lakes  and  rivers  of  the  United  States.     The  water 
supplies    of   New  York,    Boston,    Baltimore,   and    many 
other  cities,  and  the  water  of  the  Tennessee  river  near 
Nashville,  have  been  at  times  thus  unpleasantly  affected. 

Fig.  1. 


odour. 


a,  6. — Black  wavy  lines  amongst  debris, 
c,  e. — Black  wavy  lines  with  brownish  coating. 
d. — Brownish  matter  apart  from  black  Unes. 

Musty,  fishy,  piggery,  horsepond-like,  are  adjectives  which 
have  been  used  to  indicate  the  kind  of  odours  complained 
of  The  odour  of  green  corn  has  also  been  noticed.  The 
taste  of  cucumbers,  oily  and  fishy  tastes,  have  also  been 
described.  These  peculiarities  of  odour  have  been  found 
to  be  associated  with  the  rapid  multiplication  and  decom- 
position during  the  autumnal  seasons  of  the  year  of 
certain  algse,  notably  the  Codosphmrium  Kuetzingianum, 
the  Anahcena  fios-aqum,  var.  eirdnalis,  and  the  Clathro- 
cystis  ceruginosa.  Prof  W.  G.  Farlow  divides  -^  the  fresh- 
water algse  into  two  groups :  those  which  are  grass-green 
or  yellowish  green,  and  those  which  are  bluish  green  or 

•^  Paper  on  "Some  Impurities  of  Drinking  Water." 
C 


18  THE    DETEEMIXATIOX    OF    THE    AMOUNT    AXD 

purplish,  the  colour  being  due  to  a  mixture  of  chlorophyl, 
the  green  (soluble  in  alcohol),  and  phycocyanin,  the  bluish 
(soluble  in  water)  colouring  matters.  Whilst  the  former 
group  is  quite  harmless,  to  the  presence  and  decay  of  the 
latter  are  ascribed  some  of  the  most  disagreeable  odours 
and  tastes  found  in  drinking-water.  The  innocuous  grass- 
green  species  belong  to  three  different  orders,  the  Zoos- 
porese,  the  ^dogonic8e,and  the  Conjugateae,  whilst  the  bluish 
green  algse  are  placed  by  botanists  in  the  order  Phycoch- 
romacese,  a  sub-order  of  which  forms  the  family  of  the 
Nostocs — a  name  which  has  been  applied  to  the  whole 
group.  ^  With  regard  to  the  peculiar  cucumber  taste  of 
waters  above  alluded  to.  Prof  Ira  Eemsen  discovered 
that,  in  the  case  of  the  Boston  Water  Supply,  it  was  due 
to  the  presence  and  decomposition  of  a  large  quantity  of 
a  branched  form  of  freshwater  sponge  named  Spongia 
an  increase  of  the  albumenoid  ammonia  of  the  water 
fluviatilis,  spicules  of  which  were  found  in  the  mud  at  the 
bottom  of  the  reservoir.  A  chemical  examination  showed 
during  the  period  of  the  existence  of  the  unpleasant  taste. 
With  respect  to  the  question  as  to  whether  these  minute 
algse  give  an  unwholesome  character  to  water,  the  ]\Iassa- 
chusetts  State  Board  of  Health,  as  the  resu.lt  of  an 
investigation,  concludes  (and  Prof  Eipley  Nichols  agrees 
with  it^)  that  the  evidence  "tends  to  show  that  the 
plant  acts  mechanically,  chiefly  perhaps  like  unripe  fruit, 
when  affectmg  the  health  at  all,  in  causing  diarrhcea ; 
but  that  the  filtered  water  is  harmless."  A  case  is  re- 
corded, however,  in  Nature,  xviii.  (1878),  page  11,  where 

^  These  unpleasant  odours  are  not  confined  to  certain  American  \^'aters, 
for  complaints  Avere  made  some  j'ears  ago  of  the  fish-like  odour  of  the  Avater 
supplied  to  Amsterdam  from  the  "  Duins  "  (sandhills)  in  the  neighbourhood 
of  Haarlem.  The  deposit  of  this  water  was  found  on  microscopic  examina- 
tion by  H.  Medlock  {Philosophical  Magazine,  Januarj'  1S5S)  to  consist  of 
the  filaments  of  dead  and  decaA'ing  algte,  etc. 

^    JFater  Siopjjly — Chemical  and  Sanitary. 


NATURE  OF  THE  ORGANIC  MATTER         19 

cattle  had  been  poisoned  by  drinking  pond  water  containing 
large  quantities  of  a  species  of  Nodularia — a  plant  which 
resembles  the  Anabcena.  ISTo  remedy  to  obviate  the 
recurrence  of  these  annoying  odours  and  tastes  in  public 
water  supplies  has  been  proposed  beyond :  (1)  the  clearance 
of  weeds  and  substances  in  which  the  Nostocs  may  lodge  ; 
(2)  the  prevention  of  a  rapid  fall  in  the  level  of  the  water 
in  hot  weather,  and  of  the  passage  of  steam  or  hot  water 
into  streams  which  feed  reservoirs ;  and  (3)  the  substitu- 
tion of  gravelly  for  muddy  bottoms.  Large  and  deep 
bodies  of  water  would  seem  to  be  less  likely  to  be  affected 
than  small  dirty  and  shallow  reservoirs.  As  the  branched 
form  of  the  Spongia  fluviatilis  is  reputed  to  be  the 
favourite  food  of  swans,  it  would  be  well  to  intro- 
duce these  birds  during  the  autumn  months,  when 
cucumber  flavour  begins  to  be  noticed,  to  some  of  the 
affected  lakes. 

2.  The  "  Keeping  Powers  "  of  a  Water. 

The  rapid  development  of  animal  and  vegetalDle  life 
is  as  a  rule  a  sure  indication  of  the  presence  of  organic  "Keeping 
matter  in  a  state  of  decomposition.  The  property  ^°^|f^'^^'"^^ 
possessed  by  a  water  of  "  keeping  "  for  a  greater  or  less 
length  of  time,  without  undergoing  any  change  perceptible 
to  the  unaided  eye,  has  been  employed  as  a  gauge  of  the 
purity  of  a  water.  That  a  pure  water  can  be  preserved 
unchanged  for  a  considerable  time,  and  that  an  impure 
water  will  soon  become  altered  in  appearance,  are 
undoubted  facts.  It  is  equally  true,  however,  that  some 
waters  of  the  greatest  purity  will,  very  soon  after  removal 
from  their  sources,  be  found  to  display  vegetable  life  ;  for 
example,  some  artesian  waters,  that  possess  a  large 
amount  of  free  ammonia.  The  temperature  of  the  air 
has,  of  course,  much  to  do  with  the  "  keeping  powers  "  of 


20  THE    DETERMINATION    OF   THE    AMOUNT    AND 

a  water ;  life  and  growth  being  more  active  in  hot  than 
in  cold  weather. 

3.  The  Colour  Test. 

It  is  helpful  in  forming  an  opinion  as  to  the  quality 
of  a  water  to  pay  a  certain  regard  to  its  colour,  although, 
apart  from  other  indications  of  its  condition,  no  reliance 
should  be  placed  on  this  test.  Speaking  generally,  it 
may  be  said  that  waters  of  great  purity  exhibit  a  bluish 
hue,  that  waters  polluted  by  filth  have  various  shades  of 
a  straw  or  brownish  tint,  deeper  in  proportion  to  the 
amount  which  they  contain,  whilst  peaty  waters  generally 
display  a  nutty -brown  colour.  To  this  rule  there  are 
many  exceptions.  A  water  may  possess  a  strong  brown 
or  yellowish  tint  and  yet  be  free  from  filth — e.g.  some 
peaty  waters,  and  waters  containing  iron.-^  Certain 
artesian  waters  of  great  purity  have  a  straw  tint.  The 
Loch  Katrine  water,  which  suppHes  the  city  of  Glasgow, 
displays  a  colour  apparent  to  every  one.  On  the  other 
hand,  some  waters  that  are  as  devoid  of  colour  as  distilled 
water,  and  exhibit  a  greater  brilhancy,  are  found  to  be 
polluted  with  a  large  amount  of  animal  filth.  A  water 
may  be  almost  colourless  and  yet  exhibit  on  analysis 
much  vegetable  matter,  e.g.  the  water  supply  of  Bourne- 
mouth. A  water  may  be  colourless  and  still  contain  peat, 
for  white  peat  is  occasionally  met  with,  w^iich  is  a  form 
of  incompletely  carbonized  vegetable  matter.  Practically, 
however,  peaty  waters  present  various  shades  of  a  brownish 
olive-green  colour,  passing,  if  the  peaty  matter  is  in  larger 

•^  The  iron  existing  in  certain  waters  in  a  soluble  form  becomes  often 
oxidized  and  changed  into  an  insoluble  hydrated  sesquioxide  on  exposure 
to  the  air.  Such  algse  as  depend  for  their  growth  on  the  presence  of  a 
soluble  iron  salt  are  sometimes  found  in  such  waters,  especially  the 
Creuothrix  Xtihuiaua.  The  water  supplies  of  Berlin,  Halle,  Leipsic, 
Lille,  and  Ingatestone,  have  been  injured  in  this  waj^ — Yide  Water 
Sup2)ly,  Chemical  and  Sanitary,  by  Prof.  Ripley  Nichols. 


NATUEE  OF  THE  OEGANIC  MATTER         21 

quantity,  throiigli  a  nutty-brown  to  a  coffee  colour,  when 
the  peat  is  old  and  abundant.  The  following  general 
conclusions  as  to  the  teaching  of  the  tioo-foot  tuhe  (to 
be  presently  described)  respecting  peaty  waters  have  been 
published  by  Dr.  Tidy  ^ : — 

1.  Peat  producing  a  colour  short  of  an  olive-green  tint, 
invisible  in  a  quart  decanter,  is  less  than  "1  grain  per 
gallon. 

2.  Peat  affording  a  colour  short  of  a  brown  tint, 
invisible  in  a  quart  decanter,  varies  from  •!— '2  grain  per 
gallon. 

3.  Peat  furnishing  a  colour  more  or  less  brown, 
perceptible  in  a  quart  decanter,  varies  from  •2—5  grain 
per  gallon. 

4.  Peat  yielding  a  porter  colour  is  present  in  about 
1  grain  per  gallon. 

5.  Peat  giving  a  black  colour  is  present  in  about  2 
grains  per  gallon. 

Waters  from  different  sources  are  often  proposed  for 
the  supply  of  a  town  or  village  with  the  object  of  select- 
ing that  one  which  is  in  all  respects  the  best.  If,  on 
analysis,  two  or  three  of  the  collection  should  appear  to 
be  equally  good,  the  one  possessing  the  least  colour  should 
be  preferred. 

It  has  been  proposed  to  measure  definitely  the  colour 
of  water  in  two  or  three  ways.  Mr.  Crookes,  Drs.  Odling 
and  Tidy  employ  ^  two  hollow  wedges,  one  filled  with  a 
brown  solution  (made  by  dissohing  ferric  chloride  and 
cobalt  chloride  in  distilled  water,  in  such  proportions 
that  one  litre  contains  "7  gramme  of  metallic  iron,  and 
"3  gramme  of  metallic  cobalt  with  a  very  slight  excess 
of  free   hydrochloric   acid),  and   the    other   with  a   blue 

^   "River  "Water,"  in  Journal  of  Chemical  Society,  vol.  xxxvii.  1880. 
2  Report  on  the  Comp.  and  Quality  of  the  "Water  supplied  to  London, 
No.  III.  1881. 


22  THE    DETERMINATION    OF    THE    AMOUNT    AND 

solution  (made  by  dissolving  1 0  grammes  of  pure  crystal- 
lized sulphate  of  copper  in  one  litre  of  distilled  water). 
These  wedges  are  made  to  shde  across  each  other  in  front 
of  a  circular  aperture  in  a  sheet  of  metal,  so  permitting  the 
]Droduction  of  any  desired  combination  of  brown  and  blue. 
Each  prism  is  graduated  along  its  length  from  1  to  40, 
the  figures  representing  millimetres  in  thickness  of  the 
solution  at  that  particular  part  of  the  prism.  On  a  level 
just  below  the  prisms  is  a  two-foot  tube  containing  the 
water  under  examination,  and  havmg  in  front  of  it  a 
circular  aperture  of  the  same  size  as  that  in  front  of  the 
prisms.  The  stand  supporting  the  prisms  and  tube  is 
placed  horizontally  before  the  window.  The  observer 
compares  the  two  disks  of  light  presented  by  the  aper- 
tures, and  adjusts  the  prisms  until  the  colours  of  the  two 
exactly  correspond.  A  metal  pointer  affixed  over  the 
centre  of  the  upper  disk,  shows  on  the  prism  scales  the 
number  of  millimetres  in  thickness  through  which  the 
light  has  passed  to  produce  a  colour  which  corresponds 
exactly  with  that  of  the  water.  The  results  are  recorded 
in  the  following  way:  thus,  "  February  21  (New  Eiver  Co. 
Water)  20  :  21,"  an  entry  which  means  that  on  that  day 
the  colour  of  this  water,  seen  through  a  two-foot  tube, 
was  represented  by  20  mm.  of  brown,  superimposed  on 
2 1  mm.  of  blue  solution. 

s  The  method  pursued  by  Mr.  F.  King,  Analyst,  of 
Edinburgh  ^  is  the  simplest,  and  in  my  hands  has  proved 
very  satisfactory.  It  consists  in  passing  a  standard 
aqueous  solution  of  caramel  into  distilled  water  in  sutfi- 
cient  quantity  to  match  the  tint  of  the  water  under 
examination.  The  preparation  of  the  standard  is  some- 
what troublesome,  but  when  once  made,  it  will  remain 
unchanged  for  a  considerable  time. 

A   solution    of   ammonium    chloride    3  "17    grains   in 
^  Chemical  News,  March  25,  1875. 


NATUEE  OF  THE  OEGANIC  MATTEE 


23 


10,000  grains  of  distilled  water  ("0001  grains  of  ammonia 
in  1  grain  of  solution)  is  first  made  ;  1 0  grains  by  volume 
of  this  solution  is  poured  into  8  oz.  of  ammonia-free  dis- 
tilled water  contained  in  a  glass  tube  12  inches  high, 
and  25  grains  by  volume  of  ISTessler's  solution  are  added. 
This  ammonia  solution,  after  resting  for  ten  minutes  at 
a  temperature  of  60°  F.,  assumes 
a  distinct  yellowish  brown  tint. 
To  8  oz.  of  distilled  water  placed 
in  another  glass  tube  12  inches 
high,  add  sufficient  of  a  strong 
aqueous  solution  of  caramel  to 
match  the  tint  of  the  ammonia 
solution.  Some  of  the  caramel 
standard  thus  formed  is  placed 
in  a  burette  graduated  into  grains. 
A  pair  of  two-foot  tubes,  exactly 
similar,  and  at  least  ^  inch  in 
diameter,  sealed  up  at  their  lower 
extremities,  provided  with  reflect- 
ing mirrors,  and  at  such  a  distance 
from  each  other  that  both  eyes 
can  easily  look  down  their  whole 
length  simultaneously,  are  now 
brought  into  requisition. 

One  tube  is  filled  with  the  water  -"S  Xf^^-feet  iniength. 
under  examination,  and  the  other  cm -vuTcan^te'rhfo^f  ^^^'^^^ 
tube  is  nearly  filled  with  distilled  ««--Tiiin  glass  sqSares. 
water.  Sufficient  of  the  standard  caramel  solution  is 
dropped  from  the  burette  into  the  distilled  water  to  match 
the  tint  of  the  water  under  examination,  when  the  tube  is 
filled  to  the  summit.  A  piece  of  thin  glass,  about  an  inch 
square,  covers  the  overflowing  end  of  each  tube,  and  a 
comparison  between  the  two  tubes  verifies  the  accuracy 
of  the  imitation.      The  quantity  of  the  caramel  standard 


Colorimeter. 


24  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

solution  employed  is  read  off,  for  every  10  grains  corre- 
sponds with  one  degree  of  the  colour  scale. 

The  kind  of  colour  and  its  depth  are  data  which 
should  always  be  obtained,  for  the  colour  gives  an  indica- 
tion of  the  kind  of  organic  matter  present,  and  its  depth 
is  a  guide  as  to  the  amount. 


4.  Heisch's  Test. 

This  test,  which  is  believed  to  indicate  the  presence 
of  germs  or  spores  of  the  sewage  fungus,  consists  in  the 
addition  of  1 0  grains  of  the  purest  sugar  to  5  ounces  of 
the  water,  in  a  perfectly  clean  bottle,  which  should  be 
completely  filled  by  it.  The  stopper  having  been  ac- 
curately adjusted  so  as  to  throughly  exclude  atmospheric 
air,  the  bottle  of  water  is  exposed  to  daylight  at  a 
temperature  of  about  70°  F.  The  bottle  should  be 
examined  at  intervals  of  three  hours  for  minute  floating 
white  specks  which,  if  the  water  contains  sewage,  may  be 
seen  floating  about,  provided  we  look  carefully  through 
the  water  against  a  black  cloth  suspended  behind  it. 
These  bodies  are  found  to  consist,  when  examined  by  ^ 
or  -g-  inch  objective,  of  cells  with  very  brilliant  nuclei. 
These  cells  subsequently  group  themselves  like  grapes  in 
a  bunch.  Ultimately  the  odour  of  butyric  acid  becomes 
perceptible.  Dr.  Frankland  found  that  growths  were 
producible  in  pure  water  containing  in  solution  nitrate 
of  ammonia,  phosphate  of  soda  and  sugar,  and  came  to 
the  conclusion  that  the  presence  of  phosphates  in  a  water 
is  solely  needful  to  occasion  this  phenomenon.  Mr. 
Heiscli  contends  that  the  growths  considered  by  him  as 
distinctive  of  the  existence  of  sewage  differ  altogether 
from  those  seen  by  Dr.  Frankland  as  resulting  from  the 
presence  of  phosphates.     He  holds  that  the  bodies  due 


NATUEE  OF  THE  OKGANIC  MATTER        25 

to  sewage  are  developed  without  the  presence  of  air  (he 
had  indeed  first  observed  them  in  a  liquid  saturated  with 
carbonic  acid);  whilst  those  noticed  by  Dr.  Frankland  in 
waters  containing  phosphates  will  not  form  if  air  is  ex- 
cluded, and  are  then  always  accompanied  by  bacteria, 
and  are  not  attended  by  the  formation  of  butyric  acid. 


5.  The  Zymotic  or  Microzyme  Test. 

The  water  to  be  operated  on  is  collected  by  heating 
the  tube  or  flask  intended  for  its  transportation  to  a  high 
temperature,  and  hermetically  sealing  it.  The  neck  thus 
sealed  is  broken  underneath  the  surface  of  the  water  of 
which  a  sample  is  to  be  taken.  Some  of  Pasteur's 
solution  ^  (clear  and  fresh)  having  been  boiled,  one  or  two 
cubic  centimetres  of  it  are  dropped  into  a  test  tube  that 
has  been  heated  to  395°  F.  Four  or  five  drops  of  the 
water  to  be  examined  are  then  added,  and  the  mouth  of 
the  tube  is  plugged  with  cotton  wool.  The  amount  of 
impurity  in  a  water  is  estimated  by  the  degree  of  opacity 
occasioned  by  the  quantity  of  bacteria  and  the  greater  or 
less  rapidity  with  which  this  degree  is  reached.  Micro- 
organisms are  found  in  the  purest  waters  in  an  infini- 
tesimal amount.  Their  presence  in  any  quantity  indicates 
the  co-existence  of  certain  organic  substances  in  a  state 
of  decomposition. 

Unfortunately  no  unchangeable  line  or  basis,  on  which 
comparative  examinations  of  waters  could  rest,  is  discern- 
ible in  this  or  in  the  last  described  methods. 

^  Kecipe — Crystallized  siigar,  10  grammes  ;  ammonium  tartrate,  '5 
gramme  ;  yeast  ash  (well  burnt),  "1  gramme  ;  distilled  water,  100  cub. 
cent. 


26 


THE    DETEKMIXATION    OF    THE    AMOUNT    AND 


6.  The  Oxygex  or  Foechammer  Permanganate  of 
Potash  Process. 

A.  Qualitative  JExainination. 

In  the  year  1850,  Prof.  G.  Forchammer  of  Copeu- 
hagen  proposed  ^  to  employ  a  solution  of  permanganate  of 
potasli  for  determining  the  amount  of  organic  matter  in 
water.  Permanganate  of  potash  readily  yields  oxygen  to 
many  substances  capable  of  combining  with  this  element, 
of  which  organic  matter  is  one  amongst  several  others, 
such  as  iron,  nitrites,  and  sulphuretted  hydrogen,  that  are 
liable  to  occur  in  drinking  waters.  This  chemical  change 
is  accompanied  by  the  substitution  of  a  brownish  colour 
for  the  characteristic  violet-tint  of  the  solution.  It  has 
proved,  as  a  qualitative  test  for  organic  matter,  most 
fallacious  in  its  indications. 

B.  Quantitative  Examination. 

Some  scientific  men,  such  as  Dr.  W.  A.  Miller,  Mr. 
Y.  Harcourt,^  and  Dr.  A¥oods,  have  applied  it  in  a  quan- 
titative manner  for  the  analysis  of  water  with  better 
success.       Solutions  so  different   in  streugth  ^   are  used, 

^  Trans.  Royal  Danish  Socy.,  5th  series,  Physical  and  Matliem. 
Section,  vol.  ii. 

-  "Observations  on  some  Points  in  the  Analysis  of  Potaljle  Waters," 
in  Journal  of  Chemical  Society,  May  1865,  Sec.  II.  vol.  iii.  p.  117. 

2  Variable  results  obtained  by  emjjloying  Solutions  of  Permanganate 
of  Potash  differing  in  strength. 


1  gr.  in  2520  minims — 
strength  employed  by 
Drs.M.,  H.,  and  W. 

1  gr.  in  3S40  minims — 
strength  employed  by 
Dr.  Tidy. 

Water  from  -n-ell — Typhoid 
Outbreak. 

Gr.  of  Oxygen  per  gallon. 

■176 

Gr.  of  Oxygen  'per  gallon. 
•156 

Water  from  Ilfracombe. 

■032 

•130 

Water  from  private  well  at 
Great  Baddow,  Essex. 

■oso 

;  ■lOO 

NATURE  OF  THE  ORGANIC  MATTER         27 

and  there  are  such  diverse  ways  of  employing  them,  that 
it  is  difficult,  and  in  some  cases  impossible,  to  institute  any  ■ 
«&,  comparison  between  the  results  arrived  at.  Some  add  an  ^* 
acid,  e.g.  sulphuric  acid,  and  others  add  an  alkali,  e.g. 
inilk  of  lime,  to  the  water  before  treating  it,  with  the  per- 
manganate solution.  Some  conduct  the  process  at  the 
temperature  of  140°  T.,  and  othersi>^t  the  temperature  of 
the  air.  Some  allow  the  permanganate  to  act  for  a  few 
minutes,  and  others  for  hours.  Some  who  employ  this 
test  prepare  a  solution  by  dissolving  two  grains  of  the 
pure  salt  in  10-|-  oz.  of  distilled  water.  Ten  minims  of 
this  solution  is  said  to  yield  ^qqq  of  a  grain  of  oxygen. 
The  quantity  of  the  solution  required  for  a  known  quantity 
of  the  water  is  divided  by  10,  the  result  giving  the 
number  of  thousandths  of  a  grain  of  oxygen  consumed. 
The  calculation  is  as  follows : — 

Well  water  labelled  A  B,  2  ounces  =  -^q-  of  70,000  grains  (1 
gallon)  taken  for  examination. 

22  minims  of  Sol.  Permanganate  PotasL.  required  to  give  a 
decided  j^ink  colour. 

22  X  80  =  1760  minims  necessary  for  1  gallon. 

1760-^10  =  176  which  are  thousandths  of  a  grain  of  oxygen. 

Result. —  '176  of  a  grain  of  oxygen  per  gallon. 

The  three  best  known  quantitative  processes  are  : — 
(1)  that  for  many  years  practised  by  the  late  Dr.  Letheby, 
and  now  employed  by  Dr.  Tidy ;  (2)  that  adopted  by 
Drs.  Woods  and  F.  de  Chaumont ;  and  (3)  Prof  Kubel's 
variety  of  the  permanganate  of  potash  process.  The  first 
mentioned  is  preferable  to*ither  of  the  others  ;  the  second 
is  employed  much  by  army  surgeons,  being  taught  at 
Netley ;  whilst  the  third,  which  is  conducted  at  the 
boiling  point,  is  open  to  the  suspicion  that  loss  of  organic 
matter  by  volatilization  with  the  escaping  steam  is 
inevitable.  The  higher  figures  yielded  by  Kubel's 
method    are    probably   due  to   the    increased    length    of 


IT 


28  THE    DETERMINATION    OF    THE    AMOUNT    a!!^ 

time    during    which    the    permanganate     of    potash    is 
.allowed  to   act. 


Drs.  Lethehy  and  Ticlys  Permanganate  of  Potash 
Quantitative  Process  of  Water  Analysis} 

The  following  mo|^  of  employing  the  Forchammer  or 
oxygen  process  has  been  almost  exclusively  practised  by 
Dr.  Letheby  and  his  successor. 

Before  commencing  the  analysis  the  following  solutions 
should  be  ready : — 

1.  Dilute  Sulphuric  Acid. — 1  part  of  pure  strong 
sulphuric  acid  with  3  parts  of  distilled  water. 

2.  Solution  of  Potassic  Permanganate. — 2  grains  in 
1000  septems  (x^th  of  a  gallon)  of  water.  (20  septems 
or  '04  grain  of  potassic  permanganate,  contain  '01  of 
available  oxygen.) 

3.  Solution  Potassic  Iodide. — 1  part  of  potassic  iodide 
in  1 0  of  water. 

4.  Solution  of  Sodic  Hyposulphite. —  5  "4  grains  in  1000 
septems  (x^th  of  a  gallon)  of  water.  As  a  solution  of 
this  salt  quickly  decomposes,  it  is  necessary  to  make  a 
fresh  one  A'ery  frequently. 

5.  Solution  of  Starch. — 100  septems  of  distilled  water 
to  be  placed  in  a  flask,  and  10  grains  of  powdered  starch 
having  been  added,  the  mixture  should  be  boiled  and 
filtered. 

Two  glass  flasks,  each  of  abteut  2  0  oz.  capacity,  having 

^  I  am  indebted  in  the  description  of  this  process  which  follows,  to  an 
exhaustive  paper  entitled  "The  Processes  for  determining  the  Organic 
Purity  of  Potable  Waters,"  by  Dr.  Tidy,  in  Journal  of  Chemical  Society, 
vol.  XXXV.  1879,  p.  46.  It  contains  an  account  of  a  mode  of  conducting 
the  process  which  is  an  improvement  on  that  shown  to  me  some  time 
previoiis  to  its  publication,  in  Dr.  Tidy's  laboratory,  by  his  assistant 
in  his  absence. 


NATURE  OF  THE  ORGANIC  MATTER         29 


been  thoroughly  cleansed^  500  septems  (2\)th  part  of  a 
gallon)  of  distilled  water"  are  ponred  into  each.      Take 
^ther  flasks  of  the  same  dimensions,  and  pour  the  si 
Quantity  of  the  water  to  be  epamined  into  each.     La 
each  flask  thus 


)f  a 


.  DistilH!iii»  .      (1  hour.) 

„  „  ...      (3  hours.) 

Water  under  examination  .      (1  hour.) 

•      (3  hours.) 

Any  number  of  waters  can  be* commenced  at  the  same 
time,  one  set  of  the  distilled  water  series  being  sufficient 
as  a  blank  experiment  for  all. 

(a)  20  septems  of  the  dilute  sulphuric  ^la  should  be 
added  by  the  help  of  a  pipette,  graduated  into  septems,  to 
the  contents  of  each  of  the  four  flasks. 

(&)  2  0  septems  of  the  permanganate  of  potash  solution 
should  then  be^un,  by  the  aid  of  another  similar  pipette, 
into  each  of  the  four  flasks.  ISTote  the  exact  time  of  this 
addition  of  the  solution  of  potash  permanganate,  and 
place  the  four  flasks  in  a  dark  cupboard.  If  the  pink 
colour  produced  in  the  water  under  examination  disappears 
within  the  prescribed  time  of  1  hour  or  3  hours,  which 
rarely  happens,  a  second,  and  if  needful,  a  third  or  even 
fourth  dose  yf  20  septems  should  be  added,  until  the 
colour  is  permanent.  The  change  on  adding  perman- 
ganate of  potash  may  be  thus  represented : — 

Mii208S:2  +  3H2SO^  =  2MnS04  +  K2S0^  +  3H2O  +  50. 

The  oxygen  consumed  by  the  constituents  of  the 
water  is  to  be  estimated  at  the  end  of  1  hour  in  one  of 
the  flasks  containing  the  water  under  examination,  and 
in  one  of  the  distilled  water  flasks ;  and  at  the  end  of  3 


30  THE    DETEEMIXATION    OF    THE    AMOUNT    AXD 


IIOIV 


liours    in   the   other  flask    containing    the    water    under 
amination,  and  the  other  distilled  water  flask. 
At  the  expiration  of  the  hour,  it  is  first  necessary, 
sequence  of  the  changes  to  whicli  the  solution  of  t 
sodic  hyposulphite  is  subject,  tiQ.  ascertain  its  exact  valu 
by  means  of  a  blank  experiment  with. rthe  contents  of  the 
"  distilled  water  flask  (1  hour)." 

It  is  thus  effected  : — Add  2  drops  of  the  potassic  iodide 
solution  to  the  "  distilled  water  (1  hour),"  when  the  colour 
of  a  very  weak  solution  of  iodine  is  produced,  which  sub- 
stance is  in  fact  hberated  frcfei  the  potassic  iodide,  the 
quantity  set  free  teing  Ae^endent  on  the  amount  of  potash 
permanganate  remaining  in  the  water  undecom])osed — 

MNgOsKg^OKI  +  8H,S0^  =  2MnS0^  +  6K,S0^  +  SH^O  +  51,. 

The  quantity  of  iodine  liberated  is  thus  determined. 
The  sodic  hyposulphite  solution  is  placed  in  a  burette 
graduated  into  100  septems.  Eun  it  septem  by  septem 
into  the  flask  labelled  "  distilled  water  ^1  hour),"  until 
the  yellow  colour  of  the  iodine  very  nearly  disappears. 
Then  add  a  few  drops  of  the  starch  solution,  when  a 
beautiful  blue  colour  is  produced  from  the  formation  of 
the  iodide  of  starch,  and  resume  the  dropping  of  the 
hyposulphite  solution  into  the  flask  i^ntil  the  exact  spot 
is  reached,  when  the  blue  colour  disappears.  1'hat  the 
exact  mark  has  not  been  overshot  must  be  proved 
by  the  addition  of  a  drop  of  the  solutiofl  of  the  per- 
manganate of  potash,  which  immediately  restores  the 
blue  colour.  A  similar  return  of  colour  is  observed 
after  the  flask  has  been  ai^pding  exposed'  to  the  air 
for  a  few  minutes.  Eead  offmei-amount  of  hyposulphite 
used. 

Eeaction  of  the  hyposulphite  solution  on  the  free 
iodine — 

SS.XaoOg  +  lo  =  2NaI  +  NagS^Og. 


NATURE  OF  THE  OEGANIC  MATTER         ol 

Immediately  refill  the  burette  with  the  sodic  hypo- 
sulphite solution  thus  standardized  and  examine  the  _.  ^ 
contents  of  flask  labelled  "  Water  under  examination  (17^^ 
hour),"  in  precisely  the  same  manner  noting  the  amount 
of  sodic  hyposulphite  solution  employed.  At  the  end  of 
3  hours  the  contents  of  flasks  labelled  "  Distilled  water 
(3  hours) "  and  "^Water  under  examination  (3  hours)," 
should  be  examined  in  the  same  way.^ 

Experiment. — Suppose  the  usual  amount  of  2  0  septems 
of  solution  permanganate  potash  has  been  added  in  each 
case. 

At  the  end  of  1  hour. 

Sej^tems  of  sodic  liyposulpliite  solution  required  to  com- 
bine witli  tlie  free  I  in  the  distilled  water  .  .50 

Septems  of  sodic  hj-posulpliite  solution  requii-ed  to  com- 
bine with,  the  free  I  in  the  water  under  examina- 
tion      40  .       ' 

At  the  end  of  3  hours. 

Septems  of  sodic  hyposulphite  solution  rec^uired  to  com- 
bine with  the  free  I  in  the  distilled  water         .  .50 
SejDtems  of  sodic  hyposulphite  solution  recj^uired  to  com- 
bine with  the  free  I  in  water  under  examination        .      30 

In  each  case  50  septems  of  the  sodic  hyposulphite 
solution  were   employed  in   the   blank   experiment  with 

^  Prof.  Mallet  of  the  Uuirersity  of  Yirginia  has  suggested  in  his 
Report  ou  the  Results  of  a  Supplementary  Investigation,  made  by  the 
dnection  of  the  National  Board  of  Health,  the  three  following  improve- 
ments in  this  process  : — "(1)  The  time  daring  which  the  permanganate  of 
potash  is  allowed  to  act  should  be  increased  to  at  least  12,  better  24  hours, 
severed  determinations  (on  different  samples  set  aside  at  the  same  time) 
being  made  at  such  intermediate  intervals  as  1,  3,  6,  9,  and  12  hours,  in 
order  to  trace  the  progi'ess  of  the  oxidation  ;  (2)  Instead  of  using  a  fixed 
amount  of  permanganate  of  potash  at  first,  and  adding  a  second  or  third 
3harge  only  when  the  former  has  been  completely  reduced,  there  should 
be  present  a  constant  excess  all  through  the  process  ;  (3)  It  is  desirable 
hat  the  process  be  carried  on  at  a  pretty  nearly  fixed  temperature  of,  say 
3S°  F."  (For  experiments  on  the  varying  extent  of  action  of  permanganate 
'.pon  organic  matter  in  water  at  diflerent  temperatures,  vide  Bcriclit 
VDeutscli,  Chem.  Gcscllsch.,  14,  1015.) 


32  THE    DETERMINATION    OF  THE    AMOUNT    AND 

distilled  water,  and  this  amount  is  equivalent  to  '01  of 
^^^oxygen. 

^      At  the  end  of  1  hour,  ^  .  .^ 

40  septems  of  the  sodic  hyposulphite  solution  being  used  in  •'iMj 
the  water  under  examination,   the  quantity  of  oxygen  con- 
sumed may  be  thus  found  : — 

Septems  of  Sodic  Hypo.    Septems  of  Sodic  Hypo. 
Sol.  required  by  dis-        Sol.  required  by  water 

tilled  water.  under  examination.         Oxygen. 

(A)  50  :  40  ;     :  "Ol 

•01 


50  )   -400   (   -008 
400 

Oxygen  equivalent       Oxygen  equivalent 
to  50  septems.  to  40  septems. 

(B)  -01  -  -008  =  -002     the 

quantity   of  oxygen  required   to  oxidize    the    organic    and   other 
matters  in  500  septems  of  water. 

(C)  '002  X  20  =  '04  oxygen  required  to  oxidize  organic  matters,  etc., 
in  10,000  septems  or  1  gallon  of  water. 

In  exactly  the  same  manner  the  oxj^gen  consumed  after  3  hours 
may  be  calculated.     The  calculation  may  be  simplified  thus  : — 

Let  X  =  number  of  septems  of  the  solution  sodic  hyposulphite  used 

in  the  distilled  water. 
Let  Y  =  number  of  septems  used  in  water  examined. 

If  20  septems  of  the  solution  of  potash  permanganate  have  been 
employed — 

X-Yx-20     ^  .     ,  .,. 

:rp —  Oxygen  required  to  oxidize  organic  matter  in  1 

X 

gallon  of  water. 

If  40  septems  have  been  necessary  — 

Xx2-Yx-20  ■    Ai.     .       ^^ 
= =  Oxygen  required  by  1  gallon. 

If  60  septems  have  been  added — 

Xx3-Yx-20^  .. 

— =  Oxygen  required. 


NATURE  OF  THE  ORGANIC  MATTER 

Drs.  Frankland  and  Tidy  have  suggested'^  the  following 
Scale  of  Classification  : — 


Rules. 


Upland  Surface  Water. 

Water  other  than  Upland 
Surface. 

Class  1.   Great  organic  purity. 

Water  absorbing  from  permangan- 
ate of  potash  not  more  than  "07 
grain  of  oxygen  per  gallon. 

Not  more  than  "035  grain  per 
gallon. 

Class  2.  Medium  iiurity. 

From  '07  to  •21  grain  per  gallon. 

From  '035  to  "1  grain  per  gallon. 

Class  3.  Doubtful  purity. 

Absorbing  from   '21    to    '28   grain 
per  gallon. 

From  "1  to  'IS  grain  per  gallon. 

Class  4.  Imjmre. 

Absorbing  more  than  -28  grain  per 
gallon. 

More  than  '15  grain  per  gallon. 

Dr.  Tidy  evidently  leans  to  the  opinion  that  the 
putrescent  easily  oxidized  animal  organic  matters  are  oxi- 
dized within  the  first  hour,  whilst  the  oxidation  of  vegetable 
organic  matter  does  not  begin  until  after  the  second  hour. 
Prof.  Mallet  and  his  assistants,  however,  found  that  the 
proportionate  consumption  of  oxygen  within  the  first  liour 
is  rather  greater  for  those  waters  containing  vegetable  than 
for  those  containing  animal  matter.  My  own  experience 
shows  that  those  matters  which  are  in  an  actively  putre- 
scent condition,  be  they  vegetable  {e.g.  decomposing  starch), 
or  be  they  animal,  are  more  rapidly  acted  on  by  the  per- 
manganate of  potash  than  those  which  are  in  a  com- 
paratively fresh  state. 


Brs.  Woods'  and  F.  de  Chaumont's  Permanganate  of 
Potash  Process. 

1.  Introduce  into  a  flask  250  c.  c.  of  the  water  to  be  Estimation 
examined,  and  add  to  it  about  5  c.  c.  of  dilute  sulphuric  °^*°*^^\jjg 


^  Dr.  Frankland  on  Water  Analysis  for  Sanitary  Fxhrposes. 
D 


matter. 


34  THE   DETERMINATION    OF    THE    AMOUNT   AND 

acid  (1  part  of  the  strong  pure  acid  to  10  parts  of  dis- 
tilled water).  Drop  into  the  acidified  water  a  solution  of 
the  permanganate  of  potash  ("395  gramme  of  the  salt 
dissolved  in  one  litre  of  distilled  water :  1  c.  c.  yields  •! 
of  a  milligramme  of  oxygen  in  presence  of  acid)  sufficient 
to  make  the  water  pink ;  then  warm  this  pink  mixture 
up  to  140°  Y.,  taking  care  to  add  more  permanganate 
of  potash  solution  should  the  colour  disappear  during 
heating.  When  this  temperature  is  reached,  take  away 
the  lamp,  and  continue  adding  the  permanganate  of  potash 
solution,  until  a  pink  colour  is  established  that  is  per- 
manent for  ten  minutes.  Note  the  number  of  cub.  cents. 
of  permanganate  of  potash  solution  employed,  and  record 
them  as  required  for  total  oxidizable  matter. 
ff^oxitoa°bie  ^-  Take  another  250  c.  c.  of  the  same  water,  and  add 
organic  to  it  5  c.  c,  of  dilutc  sulphuric  acid.  Boil  the  acidified 
'water  for  twenty  minutes.  Allow  it  to  cool  down  to 
140°  F.,  and  then  test  with  permanganate  of  potash 
solution  as  before.  Record  the  amount  used  as  required 
for  oxidizable  organic  matter  only. 

3.  The   difference   between   the   amount   of   perman- 
acid.  ganate  of  potash  solution  needed  in  the  first  and  second 

operations   represents  the    quantity  required  for   nitrous 
acid  only. 

Examples. 
Total  Oxidizahle  Matter. 

250  c.  c.  or  ^  litre  of  sample  of  water  employed. 
No,    1. —  4"2    c.   c.   of  permanganate   of  potash   solution 

required: — 4'2  x  4=  16'8  c.  c.  per  litre. 
16-8  X -0001   (co-efficient  for  oxygen)  =  -00168  or  1-68 

milligramme  of  oxygen  for  total  oxidizahle  matter. 

Oxidizable  Organic  Matter. 
250  c.  c.  or  ^  litre  of  sample  of  water  employed. 


Estimation 
3f  nitrous 


NATURE  OF  THE  OEGANIC  MATTER     •    35 

'No.   2.  —  3 "6   c.   c.   of  permanganate   of  potash   solution 

required  : — 3-6  x  4  =  14'4  c.  c.  per  litre. 
14-4  X -0001  (co-efficient  for  oxygen)  =  '00144  or  1-44 

milligramme   of  oxygen  for   the   oxidizdble  organic 

matter. 

Nitrous  Acid. 

No.  3. — The  difference  between  the  amount  of  total 
oxidizable  matter  (1*68  milligramme  per  litre) 
and  that  of  the  organic  oxygen  (1*44  milligramme 
per  litre)  is  "24  milligramme  per  litre  of  oxygen. 

•24  X  2 '8 7 5  (co-efficient  to  convert  oxygen  into  nitrous 
acid)  =  "6 9  milligramme  of  nitrous  acid  per  litre. 

Total  Oxygen.  |  Organic  Oxygen.  |  Nitrous  Acid 


Milligramme  per  Litre. 


1-68.        I        1-44.         I        -69. 

The  permanent  pink  colour  established  by  adding  the 
]3ermanganate  of  potash  solution  to  the  sample  of  water 
must  be  the  lightest  tint  distinctly  visible.  As  about 
•6  c.  c.  of  the  solution  will  give  a  red  or  pink  colour  to 
a  litre  of  pure  water,  a  correction  for  colour  must  be 
made  when  great  accuracy  is  required.  This  correction 
would  amount  to  "06  of  a  milligramme  of  oxygen  in  both 
the  total  and  the  organic  oxygen.  Dr.  "Woods'  investiga- 
tions, on  which  this  process  is  based,  may  be  found  in 
the  Journal  of  the  Chemical  Society  for  1861.  In 
1868-69,  Dr.  F.  de  Chaumont  made  other  observa- 
tions which  improved  this  process,  by  showing  : — (1)  that 
when  water  polluted  with  sewage  was  boiled  with  acid, 
no  change  in  its  behaviour  with  permanganate  of  potash 
was  produced ;  (2)  that  if  the  organic  matter  in  it  was 
mingled  with  nitrites,  all  of  the  nitrous  acid  contained  in 
them  could  be  boiled  away  in  twenty  minutes  without 
material  loss  in  the  operation ;  and  (3)  that  the  reaction 


36        •  THE    DETERMIXATIOX    OF    THE    AMOUNT    AND 

of  the  mixture  equalled  the  sum  of  the  reactions  of  the 
two  estimated  separately. 

It  has  been  found  that  the  action  of  permanganate  of 
potash  is  slow  and  imperfect  in  the  cold,  when  each 
equivalent  only  gives  off  three  instead  of  five  atoms  of 
oxygen,  but  that  the  organic  matter  is  acted  on  rapidly 
when  the  temperature  is  raised.  Dr.  E.  de  Chaumont, 
unhke  Drs.  Letheby  and  Tidy,  does  not  give  any  opinion 
respecting  the  amount  of  organic  matter  in  a  water.  He 
neither  declares  that  it  is  eight  or  nine  (as  Dr.  Tidy 
asserts)  nor  twenty  times  (as  Dr.  Woods  stated)  the 
amount  of  oxygen  of  which  the  permanganate  of  potash  is 
robbed,  as  the  proportion  is  no  doubt  variable ;  for  the 
organic  matter  may  be  of  different  kinds  originally,  or  in 
different  stages  of  oxidation.  He  simply  and  solely 
furnishes  the  amount  of  oxygen  used  up  by  the  organic 
matter.  The  correction  necessary  in  consequence  of  the 
action  of  permanganate  of  potash  on  iron  is  but  seldom 
made  in  practice,  on  account  of  the  infrequent  (?)  occur- 
ence of  this  metal  in  drinking  water.  Allien,  however, 
this  correction  is  made,  the  iron  is  separated  by  careful 
concentration,  and  the  employment  of  the  colorimetric 
test  with  ferrocyanide  of  potassium. 

Hydrogen  sulphide,  which  affects  the  permanganate 
of  potash,  can  easily  be  detected  by  smelling  the  water 
after  violent  agitation  of  it.  This  gas  should  be  ex- 
pelled by  gently  warming  the  water  before  the  analysis 
is  commenced. 

The  pure  artesian  waters  derived  from  the  Thanet  and 
Woolwich  sandbeds,  which  contain  a  large  excess  of  free 
ammonia  {vide  page  92),  yield  a  great  amount  of  total 
oxidizable  matter  when  examined  by  this  process,  and 
but  little  organic  oxygen.  The  difference  cannot  be 
ascribed  to  nitrous  acid,  for  these  waters  are  almost 
destitute  of  such.      This  acid  may,  however,  be  produced 


NATUKE  OF  THE  OKGANIC  MATTER         37 

as  the  result  of  the  reducing  action  of  ammonia  on  the 
permanganate  of  potash. 

Rides. — 1,  A  good  water  contains  of  organic  oxygen  Rules  for 
less  than  1"0  milligramme  per  litre  (  =  "07  gr.  per  gallon).  °"'  ^^^^' 

2.  A  usable  water  contains  of  organic  oxygen  more 
than  I'O  milligramme  per  litre,  and  less  than  1"5  milli- 
gramme per  litre  ( ='^1 0  gr.  per  gallon). 

3.  A  susjjicious  water  contains  of  organic  oxygen  more 
than  1"5  and  less  than  2-0  milligrammes  per  litre  (  =  "14 
gr.  per  gallon). 

4.  A  had  water  contains  of  organic  oxygen  more  than 
2"0  milligrammes  per  litre  (  =  '14  gr.  per  gallon). 

5.  Nitrites  ought  to  be  absent  from  good  and  usable 
waters ;  their  presence  makes  waters  suspicious,  and  if 
in  marked  quantity  a  water  should  be  pronounced  to  be  bad. 

Tlie  Objections  to  the  Oxygen  or  Forchamnier 
Permangancde  of  Fotasli  Test. 

Applied  quantitatively,  by  either  of  the  two  last 
methods,  may  be  thus  summarized  : — 

1.  Permanganate  of  potash  readily  oxidizes  salts  of  objections, 
iron-,    nitrites,    and    hydrogen    sulphide,    which    are    not 
uncommonly  found  in  drinking  water.      If  there  is  any 
suspicion  afforded  by  the  taste,  or  by  a  rusty  deposit,  of 

the  presence  of  iron,  the  water  should  be  subjected  to  one 
of  the  methods  for  its  detection  described  on  page  157. 

The  detection  and  estimation  of  nitrites  or  nitrous  acid 
is  a  very  easy  matter  {vide  page  106).  If  the  presence 
of  sulphuretted  hydrogen  is  recognized  by  the  sense  of  smell 
{vide  page  1 4,  on  the  odour  of  waters)  this  gas  can  be  alto- 
gether expelled  by  warming  the  water  before  it  is  analyzed. 

2.  It  affects  but  slightly  urea,  kreatin,  sugar,  and 
gelatine,  and  does  not  act  on  fatty  matters.  Nor  does  it 
furnish  the  total  amount  of  oxidizable  matter  present  in 
a   water.      Notwithstanding    these    defects   the    perman- 


38  THE    DETEKMINATION    OF    THE    AMOUNT    AND 

ganate  of  potash  test  employed  quantitatively  is  a  useful 
auxiliary  to  the  other  methods  of  water  analysis. 

An  iTnproved  Quantitative  Oxygen  or  ForcTiammer 
Permanganate  of  Potash  Process. 

Dr.  Dupre  and  the  Society  of  Analysts  have  recom- 
mended (1)  that  stoppered  bottles  be  employed  instead 
of  flasks,  otherwise  the  test  becomes  useless  in  a  water 
containing  appreciable  quantities  of  clilorides.  Dr.  Dupre 
has  pointed  out  ^  that  "  the  test  fails  in  an  open  vessel  on 
account  of  the  mutual  action  of  permanganate  of  potash  and 
hydrochloric  acid,  whereby  the  former  becomes  reduced  and 
the  latter  oxidized  into  water  and  chlorine,  part  of  which 
escapes.  When,  however,  the  experiment  is  carried  on  in 
a  closed  vessel,  tlie  chlorine  is  retained  in  solution,  and 
when  at  the  end  of  the  experiment  iodide  of  potassium  is 
added,  this  free  chlorine  liberates  exactly  the  same  amount 
of  iodine  as  would  have  been  liberated  by  the  perman- 
ganate from  which  it  was  produced,  and  the  effect  is  the 
same  as  if  no  permanganate  had  been  destroyed  by  the 
presence  of  chlorides."  (2)  That  the  water  to  be  examined 
should  be  raised  to  a  temperature  of  80°  P.,  by  the 
immersion  of  the  bottle  in  a  water  bath  or  suitable  air 
bath,  before  the  addition  of  the  sulphuric  solution  and 
standard  potash  permanganate.  As  more  oxygen  is 
absorbed  at  that  temperature  than  at  lower  temperatures 
in  all  but  the  purest  waters,  the  water  should  be  main- 
tained at  that  temperature  for  4  hours.  If,  in  the  course 
of  the  4  hours,  the  pink  colour  of  the  water  in  the  bottle 
is  either  discharged  or  even  materially  reduced,  another 
dose  of  standard  permanganate  must  be  added,  as  the 
water  must  be  always  kept  strongly  tinted. 

The  bottle  should  be  in  the  dark  during  the  period 

1  Analyst,  July  1885,  p.  118. 


NATUEE  OF  THE  ORGANIC  MATTER         39 

when  the  water  is  under  the  influence  of  the  permanganate 
of  potash.  The  1  hour  observation  practised  by  Dr.  Tidy,  and 
the  ^  hour  observation  by  the  Society  of  Analysts,  are  not 
of  much  value,  for  the  information  afforded  by  these  brief 
exposures  which  is  arrived  at  in  other  and  better  ways, 
does  not  compensate  the  operator  for  the  additional  labour. 

7.  The  Wanklyn,  Chapman,  and  Smith  Process, 

consists  in  the  estimation,  by  means  of  ISTessler's  test,  of 
the  amount  of  ammonia  present  in  a  water  before  and 
after  it  is  distilled  with  a  solution  of  permanganate  of 
potash  and  a  large  excess  of  caustic  potash — a  mixture 
which  possesses  the  property  of  converting  organic  matter 
into  ammonia.  ISTessler's  test,  named  after  its  discoverer, 
is  an  alkaline  solution  of  the  iodide  of  mercury  {vide 
recipe  on  page  216),  and  is  capable  of  detecting  1  part 
of  ammonia  in  20,000,000  parts  of  water.  The  addition 
of  ISTessler  test  to  the  distillate  of  a  water  containing 
ammonia  is  attended  by  the  production  of  a  yellowish 
brown  or  amber  tint,  similar  to  that  of  sherry,  due  to  the 
formation  of  the  iodide  of  tetramercurammonium,  the 
depth  of  which  is  measured,  as  it  varies  according  to  the 
amount  of  ammonia  present.  Some  consider  that  it  is 
only  sufficient  to  add  a  small  quantity  of  the  ISTessler  test 
to  the  water  to  be  examined  for  organic  matter,  and  that 
the  depth  of  the  brownish  tint  produced  exhibits  the 
amount  of  organic  impurity.  The  ISTessler  test  is  simply 
a  test  for  ammonia,  and  is  not  a  test  for  organic  matter 
until  that  organic  matter  has  been  converted  into  ammonia, 
by  boiling  it  with  permanganate  of  potash  and  a  large 
excess  of  caustic  potash. 

Distillation  of  the  water  to  be  examined  for  ammonia 
adds  to  the  delicacy  of  the  process,  for  ammonia  admits 
of  concentration,  and  minute  quantities  are  more  visible 
in  a  small  quantity  of  water  than  in  double  the  amount. 


40  THE    DETERMINATION    OF    THE    AMOUNT    AND 

Distillation,  moreover,  by  the  separation  of  the  salts  in 
a  water,  such  as  magnesium  chloride,  etc.,  prevents  the 
milkiness  often  created  on  the  addition  of  the  Nessler 
re-agent,  which  interferes  materially  with,  if  it  does  not 
altogether  prevent,  a  correct  estimation  of  the  quantity 
of  ammonia  contained  in  a  water.  I  cannot  too  strenu- 
ously urge  on  analysts  the  importance  of  the  relation 
between  the  free  ammonia  in  a  water  and  that  developed 
by  the  caustic  and  permanganate  of  potash  solution,  for 
on  it  is  mainly  based  the  indication  as  to  the  Mncl  of 
organic  matter  contained  in  a  water.  The  manner  in 
which  the  ammonia  distils  over  is  a  matter  also  of  im- 
portance. Both  of  these  subjects  will  more  properly  be 
discussed  in  the  chapter  entitled,  "  The  Formation  of  an 
Opinion,  and  Preparation  of  Eeport,"  page  188.  Before 
describing  this  process  it  will  be  useful  to  direct  attention 
to  the  apparatus,  chemicals,  and  solutions  required  {vide 
pages  43,  216,  and  548).  It  is  very  important  that  the 
greatest  cleanliness  should  be  secured  in  the  following 
chemical  operations.  The  distilled  water  employed  for 
the  final  washings  of  the  glass  vessels,  and  for  all  other 
purposes,  should  give  no  coloration  with  Nessler  test, 
otherwise  it  should  be  redistilled. 

The  process  consists  of  two  distinct  stages  —  the 
estimation  of  the  free  ammonia  and  the  calculation  of 
the  amount  of  albuminoid  ammonia,  alias  the  organic 
matter. 

JEstimation  of  the  Amount  of  Free  Ammonia,  called  hy 
some  the  Actual  or  the  Saline  Ammonia. 

Distil  a  little  distilled  water  through  the  apparatus 
in  order  to  thoroughly  cleanse  it.  If  we  know  it  to  be 
clean,  it  will  be  sufficient  to  wash  out,  by  means  of  the 
Gmelin's  wash  bottle,  the  glass  tube  of  the  Liebig  con- 


NATURE  OF  THE  ORGANIC  MATTER        41 

denser  with  a  little  distilled  water.  Fit  the  tube  of  the 
retort  carefully  to  the  tube  of  the  condenser  either 
through  the  medium  of  an  adapter  {vide  fig.  3),  or  by 
means  of  a  packing  of  paper.  The  best  plan,  perhaps, 
is  to  select  a  retort  which  possesses  a  small  tubular 
portion,  around  which  a  strip  of  clean  writing-paper  is 
rolled,  sufficient  to  make  it  screw,  not  too  firmly,  other- 
wise there  will  be  a  fracture,  into  the  condenser  tube.  It 
is  very  important  to  make  this  junction  secure,  so  as  to 
prevent  the  loss  of  steam.  Place  a  half  litre  =  500 
c.  c.  of  the  water  to  be  examined  in  the  retort  by  the 
aid  of  a  perfectly  clean  funnel  to  prevent  spilling.  If 
the  operator  can  introduce  the  sample  into  the  retort 
without  losing  a  single  drop  it  is  best  to  dispense  with 
the  funnel,  for  it  is  an  additional  article  to  keep  clean. 
To  facilitate  the  expulsion  of  the  ammonia,  it  was  formerly 
the  practice  to  drop  into  the  retort  1  gramme  of  freshly 
ignited  carbonate  of  soda.  Before  returning  the  stopper 
to  the  retort  throw  a  jet  of  distilled  water  on  it  with 
the  wash  bottle.  The  passage  of  a  very  slow  stream 
of  cold  water  through  the  Liebig's  condenser  should  be 
maintained  during  the  whole  period  of  the  distillation. 
The  distillation  should  be  conducted  slowly,  otherwise 
there  may  be  a  loss  of  ammonia  in  consequence  of  im- 
perfect condensation.  Distil  over  into  a  ISTessler  glass 
5  0  c.  c.  Add  to  the  distillate  by  means  of  a  bulb  pipette 
2  c.  c.  of  Nessler  test.  If  it  contains  ammonia  a  yellowish 
brown  or  amber  colour  is  produced ;  the  deeper  the  colour 
the  greater  is  the  quantity  of  ammonia  present  in  it.  If 
the  amount  of  ammonia  be  very  small,  the  tint  will  be 
that  of  straw.  Dr.  Charles  Smart  has  pointed  out  -^  that 
the  presence  in  a  water  of  vegetable  matter  in  a  state  of 
fermentative  change  is  indicated  by  the  development  of  a 
yellow  colour  in  the  water  on  the  addition  of  carbonate 
1  Sanitary  Water  Analysis,  1886. 


42  NATURE  OF  THE  ORGANIC  MATTER 

of  soda,  and  by  a  green  coloration  (accompanied  by  a 
haziness)  of  the  Nesslerized  distillates,  of  an  olive  or 
citron  tint,  which  masks  the  characteristic  amber  brown 
colour  produced  by  ISTessler  test  in  a  solution  of  ammonia. 
Imitate  the  depth  of  tint  by  mixing  in  a  Nessler  glass 
with  50  c.  c.  of  distilled  water  more  or  less  of  the  dilute 
standard  solution  of  ammonia  contained  in  the  burette 
and  add  2  c.  c.  of  Nessler  test.  Wait  always  about  three 
minutes  for  the  colour  to  be  developed.  Nessler  re-agent, 
which  takes  a  longer  time  to  produce  its  maximum  tint, 
is  not  sufficiently  sensitive.  (To  make  ISTessler  test 
"  quick  "  add  a  little  cold  saturated  solution  of  corrosive 
sublimate  to  it.)  If  the  tint  of  the  prepared  standard  of 
ammonia  be  too  light,  add  to  the  prepared  standard  so 
much  of  the  standard  ammonia  solution  contained  in  the 
burette  as  is  deemed  to  be  sufficient  to  match  the  tint  of 
the  Nesslerized  distillate.  If  the  colour  of  the  prepared 
standard  be  too  dark,  make  up  a  fresh  standard  containing 
less  ammonia.  In  conducting  these  colour  test  com- 
parisons it  is  always  desirable  that  the  waters  contrasted 
should  be  about  the  same  temperature.  It  is  the  practice 
of  some  analysts  to  throw  away  the  second,  third,  and 
fourth  distillates  of  50  c.  c.  that  distil  over,  as  the 
first  distillate  generally  contains  f  ths  of  the  total  quantity 
of  ammonia.  They  simply  add  to  it  ^d  in  order  to  arrive 
at  the  sum  total,  e.g. — 

If  the  first  distillate  contains  '09  milligramme  in  ^  litre 
Add  1        .  .  -03 

Total  quantity  in  the  \  litre  '12  milligramme  = 
*24  milligramme  per  litre  or  part  per  million. 

It  is  sometimes  necessary  to  Nesslerize  the  fourth  or 
last  distillate  to  assure  oneself  that  all  of  the  ammonia 
has  passed  off,  for  in  some  cases,  as  e.g.  when  urea 
is   present,   the  ammonia  may   come    off   in    the    three 


^  3  03  03 

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(3= 

44  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

last  50  c.  c.  in  increasing  instead  of  diminishing  quan- 
tities. 

Again,  if  the  water  under  examination  possesses  much 
saline  matter,  or  is  very  hard,  as  is  shown  by  the  furring 
of  the  sides  of  the  retort  during  distillation,  or  by 
"  bumping "  of  the  water,  the  second  or  third  distillate 
of  50  c.  c.  should  be  examined  for  ammonia  by  add- 
ing 2  c.  c.  of  Nessler  re-agent.  If  it  exhibits  no  colour 
whatsoever,  showing  that  all  the  ammonia  has  come 
off,  the  distillation  is  to  be  stopped.  It  is  not  wise 
to  still  further  concentrate  the  water  by  removing  a 
third  or  fourth  distillate  of  50  c.  c,  unless  absolutely 
necessary,  for  the  "  bumping "  may  become  so  great 
during  the  second  stage  of  the  process  as  to  fracture  the 
apparatus. 

Estimation  of  the  Amount  of  "  Albuminoid  Ammonia" 
alias  Organic  Matter,  called  also  Organic  Ammonia. 

The  second  stage  in  the  process  commences  by  measur- 
ing out  in  a  Nessler  glass  (kept  solely  for  this  purpose) 
50  c.  c.  of  the  caustic  potash  and  permanganate  of 
potash  solution,  and  by  adding  it  to  the  hot  water  in 
the  retort.  Eeplace  the  stopper  and  the  Bunsen's  burner. 
The  flame  of  the  burner  should  not  be  large,  otherwise 
some  of  the  colour  of  the  permanganate  of  potash  may  be 
communicated  to  the  distillate.  Give  the  contents  of  the 
retort  a  wavy  motion,  or,  better  still,  a  rotatory  motion, 
by  gently  moving  the  retort  on  its  stand,  so  as  to  prevent 
"  bumping,"  and  again  distil.  Sometimes  highly  saline 
waters  "bump"  so  exceedingly  as  to  threaten  an  accident. 
ISTever  let  the  mixture  assume  the  appearance  of  a  calm, 
for  it  portends  a  storm,  in  the  shape  of  a  sudden  bursting 
into  bubbles  and  boiling  upwards  of  the  contents.  Keep 
the  fluid  always  in  motion,  and  see  that  the  stopper  of 


NATURE  OF  THE  OEGANIC  MATTER        45 

the  retort  is  securely  fixed.  Some  persons,  in  dealing 
with  such  waters,  drop  into  the  retort  scraps  of  tobacco- 
]Dipe,  or  bits  of  recently  ignited  pumice-stone,  to  lessen 
this  "  bumping."  The  objection  to  this  practice  is, 
that  we  may  inadvertently  introduce  sources  of  error, 
for  these  substances  may  contain  organic  impurities. 
It  is  a  good  plan  in  some  cases  to  incline  the  neck  of 
the  retort  upward,  so  that  the  liquid  spirted  up  may  fall 
back  into  that  from  which  it  is  ejected.  It  is  very 
needful  to  prevent  this  "bumping,"  apart  from  the 
danger  of  fracture ;  for,  if  the  colouring-matter  of  the 
permanganate  of  potash  be  carried  over  into  the  distil- 
late, the  colour  usually  produced  by  the  ISTessler  re-agent 
is  somewhat  altered,  and  it  then  becomes  difficult,  if 
not  impossible,  to  measure  its  depth  of  tint.  Distil 
slowly  in  order  to  allow  the  caustic  potash  permanganate 
sufficient  time  to  act  on  the  organic  matter,  and  in  order 
to  avoid  imperfect  condensation  of  the  ammonia.  Three 
distillates,  each  of  50  c.  c,  must  be  taken  off,  and 
each  must  be  carefully  Nesslerized.  The  colour  of 
each  distillate  must  be  matched  exactly  in  the  manner 
above  laid  down  when  describing  the  mode  of  estimat- 
ing the  amount  of  free  ammonia,  by  adding  a  certain 
known  quantity  of  the  dilute  standard  solution  of  am- 
monia contained  in  the  burette,  to  50  c.  c.  of  distilled 
water  in  a  Nessler  glass. 

The  comparison  between  the  colour  of  the  standard 
and  the  distillate  is  made  by  placing  the  Nessler  glasses 
on  the  white  porcelain  tile,  and  by  looking  down  through 
the  columns  of  fluid  on  to  the  tile.  The  amount  of  the 
dilute  standard  solution  of  ammonia  employed  to  match 
the  tint  of  the  distillate  represents  the  amount  of  ammonia 
in  the  distillate. 

For  example,  if  the  amount  of  dilute  standard  solution 
of  ammonia  required  to  match  the  tint  of  the 


46  THE    DETERMINATION    OF    THE    AMOUNT   AND 

1st  distillate  be  5  c.  c. 
2d         ,,         „  3  c.  c. 

3d         „         ,,  1  c.  c.  we  arrive  at  these  figures — 
Alb.  Ammonia         .  .  .         .       '05 

„  „  ....       -03 

„  „  ....       -01 

Total         .  -09 

■reparation  Beginners  find  it  troublesome  at  first  to  matcli  the 
f standards,  ^^j^^^^^  witliout  making  up  several  standards  containing 
different  proportions  of  the  standard  dilute  solution  of 
ammonia.  It  has  been  suggested  by  some  that  strips  of 
glass,  and  by  others  discs,  should  be  manufactured  of  the 
various  depths  of  the  sherry  or  amber  colour,  corresponding 
to  the  different  tints  developed  by  the  Nessler  re-agent 
with  definite  quantities  of  the  dilute  standard  solution  of 
ammonia.  If  such  could  be  prepared  so  as  to  indicate 
accurately  the  various  shades,  a  great  saving  of  time  might 
be  effected.  At  one  time  I  employed  a  dozen  stoppered 
standard  comparison  bottles,  of  a  capacity  of  about  50 
c.  c.  Each  bottle  was  provided  with  known  and 
different  quantities  of  the  dilute  standard  solution  of 
ammonia,  and  immediately  filled  up  with  twice  distilled 
water.  One  c.  c,  3,  5,  7,  9,  11,  13,  15,  17,  19, 
21,  and  23  c.  c.  were  the  amounts  of  the  standard 
ammonia  selected.  To  the  contents  of  each  bottle  2 
c.  c.  of  E"essler  test  were  added.  The  weakest  standard 
contained  1  c.  c,  and  the  strongest  23  c.  c,  of  the 
dilute  standard  solution  of  ammonia.  In  making  an 
analysis,  the  contents  of  the  bottle  or  bottles  that  are 
considered  likely  to  match  the  tint  of  the  distillate  are 
poured  into  a  Nessler  glass,  and  at  its  conclusion  are 
replaced.  These  solutions  slowly  absorb  ammonia,  and 
get  slightly  darker  in  time,  or  they  decompose,  losing 
their  colour  and  precipitating  red  iodide  of  mercury. 
Sometimes  they  become  turbid,  and  sediments  are  depos- 


NATURE  OF  THE  ORGANIC  MATTER         47 

ited.  Dr.  Mills'  portable  colorimeter^  has  been  employed 
for  estimating  the  tints  of  the  distillates,  as  well  as  for 
that  of  degrees  of  turbidity,  but  is,  I  find,  of  little  help. 
Although  one  of  these  instruments  stands  in  my  labora- 
tory, it  is  never  used.  These  supposed  helps  waste  much 
time,  and  are  not  so  accurate  as  the  old  plan  of  preparing 
a  fresh  standard  solution  when  wanted.  Practice  very 
soon  enables  the  water  analyst  to  guess  very  closely  the 
amount  of  the  standard  solution  of  ammonia  which  he 
will  require  to  match  any  given  tint,  so  that  he  does  not 
often  find  the  necessity  of  making  up  a  second  standard. 
I  would  recommend  the  Medical  Officer  of  Health  to 
make  himself,  by  practice,  skilful  in  matching  tints,  rather 
than  rely  on  instruments  as  aids.  The  tapped  graduated 
Nessler  glasses,  introduced  by  Mr.  Hehner,  are  useful  to 
the  novice,  or  when  rough  calculations  are  alone  requisite. 
Some  analysts,  instead  of  distilling  over  the  four  dis- 
tillates, each  of  50  c.  c,  separately,  mix  them  together 
and  thus  Nesslerize  them.  In  so  doing  they  lose  valuable 
information,  for  it  is  important  to  note  the  proportions  in 
which  the  ammonia  distils  over  in  each  distillate.  (  Vide 
the  opinion  of  Prof.  Mallet  on  page  208.)  Sometimes  a 
water  yields  nearly  equal  instead  of  decreasing  quantities 
of  ammonia,  so  that  it  is  almost  impossible  to  extract  all 
the  ammonia  from  a  water  before  the  distillation  is 
at  an  end.  This  experience  may  occur  in  the  examina- 
tion of  waters  polluted  with  urine,  or  dirty  from  the 
presence  of  soot  (vide  page  207).  In  such  cases  it  is  good 
policy,  as  has  been  pointed  out  by  Mr.  Sidney  Eich,^ 
to  Nesslerize  the  first  50  c.  c,  and  to  return  into 
the  retort  the  succeeding  150  c.  c.  that  are  distilled 
over,  of  course  Nesslerizing  the  distillate  or   distillates 

^  Described  in  Proc.  of  Glasgoiv  Philosoph.  Socy.,  March  12,  1877. 
The  instrument  is  made  by  Cetti  &  Co.,  of  Brooke  Street,  Holborn, 
London.  ^  Chemical  News,  June  9,  1876. 


48  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

procured  by  this  redistillation.  It  is  of  no  practical 
utility,  in  making  sanitary  analyses  of  water,  to  estimate 
the  amount  of  ammonia  derived  from  organic  matter  that 
is  in  excess  of  "50  milligramme  per  ^  litre  =1  milli- 
gramme per  litre,  as  that  quantity  is  so  much  more  than 
is  sufficient  to  condemn.  If  it  is  desirable  to  measure 
the  exact  amount  of  the  large  quantity  of  ammonia 
evolved,  a  funnel  tube  with  a  glass  stopcock  should  be 
adjusted  by  the  help  of  a  perforated  cork  in  the  retort 
through  the  stoppered  opening,  so  that  ammonia-free 
distilled  water  may  be  introduced  in  order  to  maintain 
the  volume  of  the  liquid  in  the  retort  constant. 

The  process  is  now  at  an  end.  Allow  the  retort  to 
remain  uncleansed  until  another  analysis  is  to  be  made, 
when  the  fur  should  be  removed  by  strong  hydrocliloric 
acid  and  an  abundance  of  water.  As  half  a  litre  has 
been  taken  for  analysis,  multiply  the  results  by  2,  in  order 
to  make  them  give  the  proportion  for  the  litre.  In  the 
foregoing  analysis,  then,  the  results  are  the  following : — 

Free  ammonia,  "24  milligramme  per  litre  =  part  per  million. 

Albuminoid  ammonia,    '18  do.  do. 

I  should  like  to  indelibly  print  on  the  minds  of  all 
water  analysts  the  following  truth : — If  you  rely  solely 
on  the  indications  of  this  process,  you  will  sometimes 
come  to  a  correct  conclusion  as  to  the  quality  of  a  water, 
but  very  often  a  mistake  will  be  made.  Couple  the 
evidence  afforded  by  it  with  other  evidence  of  a  chemical 
and  microscopical  character,  and  an  error  will  never  be 
committed.  I  regard  this  process  as  a  most  valuable  aid 
to  the  formation  of  an  ox3inion  by  the  Medical  Officer  of 
Health  as  to  the  nature  of  a  water,  as  indispensable  indeed 
as  is  auscultation  to  the  physician  in  the  diagnosis  of  lung 
and  heart  diseases.  The  e^ddence  afforded  by  the  stetho- 
scope is  brought  by  him  in  juxtaposition  to  other  evidence 


NATUEE    OF    THE    ORGANIC    MATTEE  49 

bearing  on  the  same  point,  and  an  opinion  is  formed  from 
the  sum  total  of  all  the  evidence  which  is  forthcoming. 
No  physician  dreams  of  relying  solely  on  the  character  of 
the  sounds  heard  from  the  lung  by  his  ear,  and  of  shutting 
himself  away  from  all  other  sources  of  information.  It 
appears  that  a  member  of  the  Society  of  Public  Analysts, 
who  holds  two  public  analytical  appointments,  believes 
that  the  determination  of  the  free  and  albuminoid 
ammonia  is  all  that  is  necessary  for  forming  an  opinion 
on  the  quality  of  a  drinking  water,  and  he  pronounces  a 
verdict  solely  on  the  evidence  afforded  by  these  two 
estimations.  Mr.  Allen  points  out,^  as  I  have  on  several 
occasions,  the  absurdity  of  such  a  proceeding,  for  the 
rain  water  of  country  places  would  certainly  be  con- 
demned as  polluted  with  filth  by  such  an  analyst. 

Elites. 

The  following  are  the  most  recent  rules  which  have  Rules, 
been  laid   down  by  Mr.  Wanklyn  for   the  guidance  of 
those  who  work  this  process  : — 

He  writes,^  "If  a  water  yield  '00  parts  of  albu- 
minoid ammonia  per  million,  it  may  be  passed  as  organi- 
cally pure,  despite  of  much  free  ammonia  and  chlorides  ; 
and  if,  indeed,  the  albuminoid  ammonia  amounts  to  "02, 
or  to  less  than  "05  parts  per  million,  the  water  belongs 
to  the  class  of  very  pure  water.  When  the  albuminoid 
ammonia  amounts  to  '05,  then  the  proportion  of  free 
ammonia  becomes  an  element  in  the  calculation ;  and  I 
should  be  inclined  to  regard  with  some  suspicion  a  water 
yielding  a  considerable  quantity  of  free  ammonia,  along 
with  more  than  "05  parts  of  albuminoid  ammonia  per 
million.      Free  ammonia,  however,  being  absent,  or  very 

^  "On  some  Points  in  the  Analysis  of  "Water,  and  the  Interpretation 
of  the  Results  ;"  by  A.  H.  Allen.     The  Anahjst,  July  1877,  p.  61. 
^    Water  Analysis.     Fourth  Edition,  p.  53. 

E 


50  THE    DETEKMIXATION    OF    THE    AMOUNT    AND 

small,  a  water  should  not  Le  condemned  unless  the 
albummoid  ammonia  reaches  somethmg  like  "10  per 
million.  Albuminoid  ammonia  above  '10  per  million 
begins  to  be  a  very  suspicious  sign;  and  over  '15  ought 
to  condemn  a  water  absolutely." 

Objections. 

Several  objections  have  been  urged  against  this  process, 
the  principal  of  which  are  : — 

1.  Taking  a  series  of  nitrogenized  bodies,  the  propor- 
tion of  nitrogen  procured  in  the  form  of  ammonia  is  not 
obtained  in  definite  and  simple  fractions,  but  varies  widely. 
The  value  of  the  process  is  not  impaired  because  piperine 
yields  the  whole  of  its  nitrogen  as  ammonia,  because 
morphia  yields  one  half,  or  theine  yields  one  quarter, 
whilst  albumen  yields  two-thu-ds ;  for  piperine,  morphia, 
theine,  and  shnilar  bodies  are  not  usual  constituents  of 
well  water.  It  has  been  remarked  by  Dr.  Tidy  that  the 
importance  of  the  Hct  that  organic  bodies  yield  their 
nitrogen  as  albuminoid- ammonia  in  different  proportions  is 
much  overrated,  if  the  yield  of  albuminoid  ammonia  is 
found  to  keep  pace  with  the  purity  or  impurity  (as  the  case 
may  be)  of  waters.  Messrs.  Wanklyn,  Chapman,  and  Smith, 
have  distinctly  affirmed  that  their  process  is  designed  for 
estimating  the  relative  quality  of  drinking  water,  and  is 
not  one  for  the  quantitative  determination  of  nitrogen. 

2.  That  the  amount  ,  of  ammonia  obtainable  from 
albumen  by  the  action  of  alkahne  permanganate  is  in- 
fluenced by  the  degree  of  concentration  of  the  solution 
and  the  rate  of  distillation.  Mr.  Wanklyn  has  stated 
most  positively  that  the  yield  of  ammonia  is  not  affected 
by  these  circumstances,  and  in  proof  of  this  assertion  re- 
fers to  a  set  of  experiments  published  by  himself  in  1867. 

3.  "If  20  grains  of  urea  were  present  in  a  gallon  of 


NATURE  OF  THE  OEGANIC  MATTER         51 

water,"  wrote  the  late  Mr.  Wigner/  "  the  sample  would  be 
passed  hj  the  AVanklyn,  Chapman,  and  Smith's  process 
as  absolutely  pure."  It  is  stated  by  Mr.  Wanklyn  that 
fresh  urea  is  not  decomposed  into  ammonia  by  distilling 
with  or  without  the  mixture  of  caustic  potash  and 
potassium  permanganate.  It  has  been  pointed  out  by 
Prof  Mallet  that  it  is  erroneous  to  assert  that  urea  is  not 
convertible  into  ammonia,  and  evidence  is  given  by  him 
to  the  contrary.^  In  the  experiments  conducted  by  Dr. 
Cory  at  the  instance  of  the  Local  Government  Board  ^  it 
was  found  that  the  statement  that  urea  yields  no  ammonia 
"is  substantially  correct,"  if  it  is  dissolved  in  distilled  water, 
but  yet  not  quite  accurate.  He  writes,  "  the  impurities 
of  a  water  will  occasion  a  much  greater  proportion  of 
ammonia  to  be  formed  from  urea."  Urea  in  a  drinking 
water  can  hardly  ever  occur  in  a  fresh  condition.  The 
ready  fermentation  of  urea  into  carbonate  of  ammonia  is 
a  peculiarity  of  urea.  The  rapidity  with  which  this 
change  takes  place  is  such  that,  in  the  examination  of 
drinking  waters  which  are  polluted  with  urine,  we  may 
be  pretty  confident  that  sufficient  of  the  urea  has  been 
decomposed  before  the  water  reaches  our  distilling  appa- 
ratus to  give  a  large  excess  of  ammonia. 

4.  The  inability  of  some  eyes  to  arrange  and  classify 
tints,  renders  it  possible  that  there  may  be  several  errors 
of  observation  in  the  comparison  of  so  many  distillates. 
If  the  analyst  has  any  defect  of  vision  approaching  to  a 
condition  of  colour  blindness,  it  is  desirable  to  receive 
all  the  ammonia  distillates  together  (unless  the  amount 
distilled  over  after  the  first  distillate  is  calculated  by 
dividing  by  3)  and  all  the  albuminoid  ammonia  distillates 
together,  thus  minimizing  this  source  of  error,  although 

^  Analyst,  March  1878.  -  Op.  idt. 

^   Vide  Eleventh  Annual   Eeport   of  the   Local   Government    Board 
1881-82,  containing  Medical  Officer's  Supplement  for  1881,  p.  127. 


52  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

by  SO  doing  valuable  information  is  lost.      (Vide  pages 
47  and  208). 

5.  "  Peaty  waters  yield  a  flood  of  albuminoid  ammonia." 
The  absence  of  any  excess  of  nitrates  and  nitrites,  as  in- 
dicated by  their  respective  tests,  shows  that  the  organic 
matter  is  not  animal  but  vegetable. 

6.  In  the  determination  of  both  "  free  "  and  "  albumi- 
noid" ammonia  there  is  a  loss  resulting  from  imperfect 
condensation  of  the  ammonia  during  distillation,  and  this 
loss  is  less  marked  in  the  estimation  of  small  quantities 
of  organic  matter  in  a  water  than  when  it  is  in  larger 
amount.  This  difficulty  may  be  overcome  by  conducting 
the  distillation  very  slowly,  or  by  connecting  to  the  end 
of  the  condenser  tube  a  Nessler  glass  to  which  a  U  tube 
containing  25  c.  c.  of  ammonia -free  distilled  water  is 
fitted,  such  as  is  employed  in  the  estimation  of  the  nitrates 
and  nitrites,  page  115,  so  as  to  catch  any  ammonia  that 
may  be  otherwise  lost. 

7.  In  some  cases  the  albuminoid  ammonia  ol^tained  as 
ammonia  is  actually  less  than  the  ammonia  known  to  be 
present  in  the  caustic  and  permanganate  of  potash  solution. 
I  do  not  remember  ever  to  have  encountered  such  an 
anomaly,  which  at  all  events  could  only  occur  in  a  water 
of  great  purity.  In  some  cases  nitrogenous  organic 
matter  is  volatilized  during  the  distillation  for  free 
ammonia,  which  if  it  had  been  retained  would  have 
yielded  up  its  nitrogen  as  albuminoid  ammonia,  such 
nitrogenous  matter  escaping  detection  under  either  head. 

These  are  the  weak  points  of  the  process  which  teach 
us  that  we  should  not  rely  on  its  indications  to  the 
exclusion  of  other  information.  The  practical  question 
answered  by  this  process  is  not,  however,  as  to  how  much 
nitrogen  is  contained  in  a  water,  but  whether  a  water  is 
wholesome  or  not. 


nature  of  the  organic  ^matter  oc) 

8.  The  Frankland  and  Armstrong  Process. 

This  process,  wliich  is  based  upon  the  principle,  that 
when  the  residue  on  evaporation  of  the  water  is  burned  with 
oxide  of  copper,  nitrogen  and  carbonic  acid  are  eliminated 
from  the  organic  matter,  consists  in  the  determination  of 
the  amount  of  organic  nitrogen  and  organic  carbon  by  a 
measurement  of  the  respective  volumes  of  these  gases. 

The  late  Prof.  Parkes,  in  his  text-book  on  Practical 
Hygiene,  writes  respecting  it: — "This  plan  requires  so  much 
apparatus,  time,  and  skill,  as  to  be  quite  beyond  the  reach  of 
medical  officers,  and  it  would  also  appear  that  in  the,  hands 
of  even  very  ahle  chemists  it  gives  contradictory  results;^  the 
quantities  are  in  fact  so  small,  and  the  chances  of  error  so 
repeated  that,  in  its  present  form,  this  really  beautiful  plan 
seems  not  adapted  for  hygienic  water  analysis.  It  is  also 
difficult  to  know  what  construction  should  be  put  on  the 
results  ;  a  water  containing  much  non-nitrogenous  organic 
matter  may  give  a  very  much  larger  amount  of  '  organic 
carbon '  than  a  water  containing  a  much  smaller  amount 
of  nitrogenous  matter,  and  yet  be  much  less  hurtful." 

The  Elvers  Pollution  Commissioners  (Sixth  Ee'port, 
page  5),  confess  that  "this  process  is  both  troublesome 
and  tedious."  It  is  generally  admitted  to  be  attended 
with  a  high  experimental  error,  and  is  considered  by 
some  as  yielding  illusory  results. 

As  it  is  quite  unadapted  to  the  wants  of  the  health 
officer,  I  shall  not  here  describe  the  process,  but  must 
refer  my  readers  to  Sutton's  Volumetric  Ancdysis,  or  Dr. 
T.  E.  Thorpe's  Quantitative  Chemical  Analysis,  page  299. 
Some  idea  may  be  formed  of  the  cumbrous  and  complicated 
nature  of  the  process  by  glancing  at  the  engravings  in 
these  works  of  two  of  the  principal  pieces  of  apparatus 
employed.      The  smaller  is  a  Sprengel's  Pump,  which  is 

^  The  italics  are  mine. 


54  THE    DETERMINATION    OF    THE    AMOUNT    AND 

attaclied  to  the  combustion  tube  in  which  the  solid 
residue  is  burnt  with  oxide  of  copper  in  a  furnace.  Tlie 
larger  is  the  apparatus  employed  for  the  analysis  of  the 
gases  thus  obtained.  Any  one  who  is  practically  ac- 
quainted with  modern  quantitative  analysis  can  learn  this 
process  in  about  a  month.  The  large  majority  of  medical 
men  wdio  are  not  provided  with  this  foundation  would 
require  a  six  months'  course  in  chemistry  to  prepare 
them  for  learning  this  process  of  water  analysis.  Again, 
the  cost  of  the  apparatus  is  a  considerable,  although  of 
course  not  an  insuperable  oljstacle  to  its  employment, 
being  as  much  as  thirteen  guineas.  Prof.  M'Leod's  ap- 
paratus for  gas  analysis,  which  is  considered  to  be  an 
improvement  on  Dr.  Frankland's,  is  still  more  complex, 
and  twice  as  costly,  being  £26  :  5s.,  whilst  the  price  of 
Thomas'  improved  modification  is  £30. 

Prof.  Mallet  thus  writes,  "  Prom  the  hands  of  a  person 
without  proper  laboratory  training  its  results  are  utterly 
valueless.  It  is  but  a  method  of  approximation,  involving 
sundry  errors,  and  in  part  a  balance  of  errors." 

The  certificate  of  an  analysis  made  by  Dr.  Prankland's 
elaborate  process  is  about  as  incomprehensible  as  the 
process  itself  to  all  who  are  not  chemical  experts  or 
analysts.  Members  of  Sanitary  Authorities  and  their 
medical  officers  often  find  these  certificates  perfectly 
unintelligible,  although  they  are  accompanied  by  ex- 
planatory notes  for  their  interpretation.  Can  anything 
be  more  confusing  to  the  public  than  the  contents  of  the 
column  headed  "  Previous  Sewage  or  Animal  Contamina- 
tion "  ?  I  recently  saw  one  of  his  certificates  of  an  analy- 
sis of  an  excellent  spring  water,  which  contained  in  this 
column  the  numbers  1710,  which  was  accompanied  by  the 
following  remark  : — "  As  this  is  spring  water  the  evidence 
of  previous  sewage  contamination  which  it  exhibits  may 
be  safely  disregarded."     The  expression  "  Previous  Sewage 


NATURE  OF  THE  ORGANIC  MATTER         5  5 

or  Animal  Contamination  "  is  a  very  unfortunate  one,  for 
it  has  given  rise  to  an  endless  amount  of  misconception. 

Animal  matters  in  passing  through  the  pores  of  clean 
soil  become  oxidized  and  converted  into  ammonia,  nitrates, 
and  nitrites,  which  are  harmless.  This  oxidation,  in 
other  words  this  beneficial  cleansing  power  of  earth,  does 
not  continue  for  an  indefinite  period.  Soil  is  liable  to 
be  in  time  overdone  with  filth,  and  is  then  unable  to 
carry  on  this  purifying  action,  so  that  the  animal  matters 
pass  through  it  unchanged.  Its  particles  require  rest  and 
free  exposure  to  the  air,  before  it  recovers  its  expended 
power.  Earth  becomes  relieved  of  the  products  of  this 
dressing  with  filth  by  means  of  vegetation,  which  greedily 
incorporates  them  into  its  substance.  "Previous  Sewage " Previous 
or  Animal  Contamination"  then,  is  the  record  of  the  pastf^^,]^fjf^'^^j^™' 
history  of  the  water,  being  the  sum  total  of  the  products 
of  animal  matter  that  have  been  oxidized,  namely,  the 
ammonia,  the  nitrates,  and  nitrites.  This  total,  after  the 
removal  of  the  average  amount  of  ammonia  in  rain,  is  re- 
presented as  the  mineral  residue  of  the  previous  animal 
contamination  of  the  water,  in  terms  of  average  London 
sewage,  100,000  parts  of  which  are  roughly  estimated 
to  contain  10  parts  of  these  three  nitrogenous  matters. 
Here  is  an  example  of  the  manner  in  which  the  figures 
in  this  column  are  obtained : — 

Nitrogen  as  nitrates  and  nitrites 
Ammonia        ...... 

Deduct  for  nitrogen  as  nitrates,  nitrites,  and 
ammonia  in  rain  ..... 

"5-881 
Add   0    and   remove  decimal   point,  and  the   figures 
58810    are   arrived   at,   which   represent   the   "previous 
sewage  or  animal  contamination."      Or  it  may  be  calcu- 
lated by  multiplying  the  sum  of  the  quantities  of  nitrogen 


5-911 
•002 

5-913 

•032 

56  THE    DETERMINATION    OF    THE    AMOUNT    AND 

present  as  nitrates,  nitrites,  and  ammonia,  by  10,000, 
and  by  subtracting  320  from  the  result.  Some  of  Dr. 
Frankland's  disciples,  perceiving  doubtless  the  extreme 
liability  to  the  misunderstandmg  of  this  expression,  have 
omitted  or  altered  it ;  for  example,  Dr.  C.  Brown's  certi- 
ficates do  not  contain  this  column,  whilst  Mr.  W.  Thorp 
has  substituted  the  term  "  total  inorganic  nitrogen,"  which 
corresponds  with  Dr.  Frankland's  "  previous  sewage  con- 
tamination," minus  the  deduction  for  the  ammonia  in 
rain.  The  "  total  combined  nitrogen  "  of  these  chemists, 
is  the  sum  of  (1)  the  organic  nitrogen;  (2)  the  nitrogen 
as  nitrates  and  nitrites ;  and  (3)  the  ammonia. 

FmUs. 

It  is  useful  for  medical  officers  of  health  and  other 
sanitarians  to  remember  the  following  rules,-"-  which  guide 
those  who  employ  this  ]Drocess,  in  order  that  they  may 
be  able  to  interpret  the  results  : — 

Quantity  of  Organic  Carlion  and  Organic  Nitrogen. — 
"  The  weight  of  the  organic  carbon  found  in  different 
samples  of  water  indicates  the  amount  of  organic  matter 
with  which  the  water  is  contaminated,  but  it  does  not 
reveal  the  source,  animal  or  vegetable,  whence  that 
organic  matter  is  derived." 

"  Cceteris  paribus,  the  smaller  the  proportion  of 
organic  carbon  the  better  the  quality  of  the  water." 

"  If  the  source  of  the  organic  matter  be  altogether 
vegetal  a  larger  proportion  of  organic  carbon  than  "2  part  in 
100,000  parts  of  water  is  undesirable,  because  it  renders 
the  water  slightly  bitter  and  unpalatable.  A  larger  pro- 
portion of  organic  carbon  if  it  be  contained  in  animal 
matter  does  not  interfere  with  the  palatability  of  the  water, 
but  it  exposes  the  consumer  to  the  risk  of  infection." 

^  Sixth  Rejiort   of  the  Eivers  Pollution  Commission,   1874,  and  W. 
Thorp's  Article  on  "Water  Analysis  in  Sutton's  Volumetric  Analysis. 


NATUEE  OF  THE  OEGANIC  MATTER         57 

Vegetable  organic  matter  is  far  from  being  destitute 
of  nitrogen  ;  for  instance,  peat  contains  much  of  it. 

"  Surface  water  and  river  water,  which  contains  in 
100,000  parts  more  than  "2  part  of  organic  carbon  or 
■03  part  of  organic  nitrogen,  is  not  desirable  for  domestic 
supply,  and  ought,  whenever  practicable,  to  be  rejected. 
Spring  and  deep  well  water  ought  not  to  possess  more 
than  •!  part  of  organic  carbon  or  "03  part  of  organic 
nitrogen  in  100,000  parts.  If  the  organic  nitrogen 
reaches  "15  part  in  100,000  parts,  the  water  ought  to  be 
used  only  when  a  better  supply  is  not  obtainable."^ 

When  the  quantities  of  organic  carbon  and  organic 
nitrogen  exceed  2'0  and  0'5  parts,  respectively,  the 
sample  may  be  considered  as  belonging  to  the  class  of 
sewages,  the  intermediate  quantities  indicating  various 
degrees  of  pollution.  Sewage  usually  contains  about  four 
parts  of  organic  carbon  and  two  parts  of  organic  nitrogen. 

PmUo  of  Organic  Carbon  to  Organic  Nitrogen. — When  Ratio, 
the  organic  matter  is  of  vegetable  origin  the  ratio  is  very 
high,  and  when  of  animal  origin  it  is  very  low.  As  a 
qualification  of  this  statement,  it  should  be  said  that  in 
the  case  of  unoxidized  peaty  waters  the  ratio  is  diminished 
by  oxidation ;  and  in  the  case  of  waters  polluted  by 
organic  matter  of  animal  origin  a  reverse  action  takes 
place,  the  ratio  being  increased  by  oxidation.  In  peaty 
waters  the  ratio  may  amount  to  as  much  as  20.  In 
sewage  it  varies  from  1  to  3.  In  unpolluted  upland 
surface  waters  the  ratio  fluctuates  from  about  6  to  12, 
and  in  water  from  shallow  wells  from  2  to  8.  The  ratio 
in  water  for  domestic  supply  may  vary  from  5  to  12,  and 
that  in  polluted  river  water  from  3  to  5. 

Frevious   Sewage   or  Animal    Contamination. — If  the  "Previous 
water  be  derived  from  a  deep-seated   spring  or  a  deep  ^^J^° ^  ^'^,j^_ 
well,   and   the   previous  sewage   contamination  does  noti-aminatiou." 
exceed   10,000  parts   in  100,000    parts  of  water,  it  is 

^  Vide  Water  Analysis,  liy  Dr.  Franklaml. 


58 


THE    DETEKMINATION    OF    THE    AMOUNT    AND 


Table  exhibiting  Different 

Result  of  Analyses  exjjressed 


Description. 

Total 

solid 

Impurity. 

Organic 
Carbon. 

Organic 
Nitrogen. 

Ammonia. 

Raix  Water        .... 

2-95 

•070 

-015 

•029 

Upland  Surface  Water    . 

9-67 

•322 

•032 

-002 

Deep  Well  Water     . 

43-78 

-061 

•018 

-012 

Spring  Water    .... 

28-20 

•056 

•013 

■001 

UjJland  Surface  Water. 

The  Teign  above  Old  Wheal,  Ex- 

mouth,  Sept.  26,  1873 

6-08 

•582 

•058 

•004 

Loch  Katrine,  the  Water  Supply  of 

Glasgow,  August  3,  1870    . 

2-40 

•185 

-022 

•001 

Surface  Water  from  Cultivated 

Land. 

The    Thames   at   Thames   Ditton, 

Jan.  31,  1873     .... 

31  36 

-325 

-076 

-003 

Shallow  Well  Waters. 

Water  from  well  at  Alford,  on  the 

Don,  Scotland,  March  8,  1872    . 

16-80 

-048 

•007 

•000 

Water    from   well   in   Well    Close 

Square,  London,  June  5,  1872   . 

396-50 

-278 

•087 

•000 

Churchyard   Well,    Leigh,    Essex, 

]Srov.'28,  1871    .... 

112-12 

-210 

•065 

-000 

Deep  Well  Water, 

Water   from    Grays,    South    Essex 

Water  Company,  Feb.  15,  1873. 

44-80 

-064 

•017 

•001 

Well  at    Waterworks,   Colchester, 

April  2,  1873     .... 

96-20 

•174 

-030 

•021 

Spring  Waters. 

Eabate  Fountain,  Balmoi'al,  March 

9,   1872 

1-40 

-119 

-014 

-000 

Spring     supplying     Town    Well, 

Southam,  Dec.  3,  1869 

57-30 

•282 

-054 

•Oil 

Beacon  Hill  Spring,  Bath,  Feb.  17, 

1871 

40-62 

•253 

•041 

-000 

Norwegian  Block  Ice     . 

-47 

•0^29 

•005 

•O05 

Sea  Water 

3898-70 

•278 

•165 

•006 

Sewage 

72-20 

4-696 

2^205 

5-520 

To  convert  parts  per  100,000  into  grains  per  gallon  and  the  Hardness 
^  Sixth  Report  of  the  Rivers  Pollution  Commission, 


NATURE    OF    THE    OKGANIC    MATTER 


Classes  of  Waters.^ 

in  parts  per  100,000. 


Nitrogen 

as  Nitrates 

and 

Nitrites. 

Ratio. 
Organic 
Carbon . 

Previous 
sewage 

Contam- 
ination. 

Clilorine. 

Hardness. 
Total. 

Remarks. 

Nitrogen. 

•003 
•009 
•495 
•383 

4-7 

10-1 

3-4 

4-3 

42 

10 

4743 

3559 

•22 
1-13 
5-11 

2-49 

•3 

5-4 
25-0 
18-5 

(  Average    Compo.sition   of 
(      Unpolluted  Waters. 

-000 
•000 

10^ 

8^4 

1-40 

•85 

2-6 
•9 

t  A  peaty  water,  which  con- 
1      tains    more    vegetable 
1      matter  than  is  admissi- 
'      ble  for  drinking. 
A  very  good  water. 

•312 

4-3 

2820 

1-75 

23^9 

'  Certain  amount  of  animal 
pollution.  Nitrates  and 
nitrites  present  from  use 
of  manures.     Most  efK- 

^     cient  iiltration  needful. 

•033 

7-0 

10 

2-85 

9^3 

Good  shallow  well  water. 

25-840 
5-047 

3-2 
3^2 

258080 
50150 

34^60 
13-75 

19r 
60- 

f  Highly  polluted  shallow 
\      well  water. 
/  Polluted     shallow     well 
\     water. 

•929 
2^582 

4- 
5-8 

8980 
25670 

5-05 
21  • 

29-4 
25-7 

C  Very  pure,  although  con- 
-]      taining  much  nitrates 
(^     from  the  chalk. 
Polluted  deep  well  water. 

•000 

8^5 

•55 

1-2 

Exceedingly  pure. 

•397 

5-2 

3740 

2^00 

33-5 

1^205 

•033 
•003 

6-0 
5-8 
1-7 
2-1 

11730 
103 

2^60 

•05 

1975-60 

10-66 

30^ 
796  9 

into  degrees  of  Clark's  Scale,  respectively,  multiply  by  -7. 
1874,  and  Water  Analysis,  by  Dr.  Frankland. 


60 


THE    DETERMINATIOX    OF    THE    AMOUNT    AXD 


reasonably  safe,  provided  all  contaminated  surface  water 
has  been  rigidly  excluded  from  the  well  or  spring. 

Eiver  or  flowing  water  which  exliibits  any  proportion, 
however  small,  of  contamination,  and  well  or  spring  water 
containing  fr-om  10,000  to  20,000  ^ar/fs  of  previous  con- 
tamination in  100,000  parts  of  water,  are  considered 
susijicious  or  clouhtful. 

Waters  more  impure  than  those  classed  as  suspicious 
must  he  regarded  as  dangerous. 

Objections. 

The  principal  are  the  following : — 

"Whilst  professing  to  measure  the  organic  bodies 
contained  in  a  water,  such  substances  are  more  or  less 
decomposed  and  dissipated  during  the  preliminary 
process  of  evaporation. 

The  experimental  error  is  often  greater  than  the  total 
quantity  to  be  measured. 

There  exists  considerable  doubt  as  to  the  accuracy  of 
the  results  when  a  water  contains  some  unstable  form  of 
organic  matter  in  'presence  of  a  htrge  excess  of  nitrates. 
There  can  be  no  question  but  that  Dr.  Frankland  is 
sometimes  inconsistent  in  his  interpretation  of  the  results 
of  his  analyses.  Here  is  an  example  : — 
Parts  per  100,000. 


Description. 

5  - 

5  & 

5g 

o 

o 

< 

111 
P  "5-3 

5-feZ 

o 

o 

Opinion. 

Water  from 

bore,    90   feet 

deep,  Clayton 
AVest    .     .     . 

•202 

•051 

3^9 

•008 

•000 

2  •45 

Good. 

Water  from 

deep  borinsf  in 

Bourne,    Lin- 
colnshire .     . 

■217 

•047 

4^6 

•000 

•000 

2^10 

Polluted. 

NATUKE    OF    THE    ORGANIC    MATTER  61 

Prof.  Mallet  states  that  the  extent  of  the  disa<?reement 
of  the  results  of  multiplied  analyses  of  the  same  water  by 
the  combustion  process  proved  in  his  hands  to  be  much 
greater  in  the  case  of  organic  nitrogen  than  in  that  of 
the  organic  carbon. 

This  conclusion  is  supported  by  the  opinion  of  Dr. 
Tidy,  that  the  results  of  the  combustion  process  are  less 
to  be  relied  on  for  nitrogen  than  for  carbon.  The 
professor  writes,  "  We  iind  loss  of  carbon  and  excess  of 
nitrogen  in  the  artificially  prepared  waters  of  known 
composition.  Our  experiments  furnish  for  the  first  time, 
so  far  as  I  know,  direct  evidence  of  the  fact  that,  for  some 
organic  substances  at  least,  and  those  of  a  kind  liable 
to  occur  among  the  products  of  putrefaction,  there  is 
material,  nay,  very  great  loss  of  carbon.  The  excess  of 
nitrogen  is,  in  part  at  least,  due  to  absorption  during 
the  e's^aporation  of  the  acidified  water  of  ammonia  from 
the  atmosphere  surrounding  the  gas  fiame  furnished  by  the 
gas  during  combustion,  partly  balanced,  no  doubt,  by  loss 
of  that  originally  present  in  the  water.  These  two  errors 
are  relatively  greatest  when  the  quantity  of  organic 
matter  in  the  water  is  smaU." 

Dr.  Dupre  writes,^  "  Sea  water  shows  a  ratio  between 
organic  carbon  and  nitrogen  worse  even  than  is  found  in 
pure  sewage !" 

The  reason  assigned  by  the  French  chemists  for  not 
employing  the  combustion  process  at  the  Municipal 
Laboratory  of  Paris  is  that  it  "  is  subject  to  many  causes  of 
error,  and  is  of  so  extremely  delicate  a  nature  as  to  be 
almost  abandoned  at  the  present  time." 

The  late  Mr.  Wigner,  the  analyst,  wrote  thus  ^  re- 
specting it  : — "  Supposing  that  the  organic  nitrogen 
yielded  by  the  Frankland  and  Armstrong  process  were  a 


1  Analyst,  July  1885. 
Sanitary  Record,  October  19,  li 


1877,  p.  256. 


62  THE    DETEKMINATION    OF    THE    AMOUNT    AND 

positive  quantity,  instead  of  a  quantity  needing  a  heavy 
correction  for  personal  equation  and  for  impurities  in  the 
chemicals  used,  yet  the  danger  of  error  involved  in  the 
process,  and  the  risk  of  contamination  by  atmospheric 
impurities,  are  in  my  opinion  sufficient  to  prevent  it 
from  ever  coming  into  general  use ;  and  unless  generally 
used,  it  is  undesirable  for  reports  which  appeal  to  public 
sense  and  public  understanding." 

Modifications  of  the  Frankland  and  Armstrong  process, 
devised  for  the  saving  of  time  and  manipulative  skill, 
have  been  adopted  by  A.  Dupre  and  H.  Wilson  Hake,-^ 
and  by  W.  Dittmar  and  H.  Eobinson.^ 

In  the  estimation  of  the  organic  carbon  the  former 
chemists  pass  the  carbonic  acid  evolved  from  the  organic 
carbon  into  baryta  water.  The  carbonate  of  baryta  is 
converted  into  the  sulphate  of  baryta,  which  is  weighed 
and  the  amount  of  carbon  calculated.  It  would  seem 
from  the  experiments  detailed  in  an  inquiry  "  On  the 
results  of  examination  of  certain  samples  of  water  pur- 
posely polluted  with  excrements  from  enteric  fever 
patients,  and  with  other  matters,"  by  Dr.  Cory,  contained 
in  the  Supplement  of  the  Eleventh  Annual  Eeport  to  the 
Local  Government  Board,  1881-82,  proof  was  afforded 
{vide  page  157)  that  the  organic  carbon  was  over- 
estimated by  Drs.  Dupre  and  Hake's  process. 

In  the  estimation  of  the  organic  nitrogen,  Messrs. 
Dittmar  and  Eobinson  burn  the  w^ater  residue  with 
caustic  soda  in  a  current  of  hydrogen,  the  ammonia 
produced  being  passed  into  very  dilute  hydrochloric  acid 
and  then  fixed  as  chloride,  the  amount  of  which  is 
estimated  by  the  Nessler  test. 

^  Chemical  Society  Journal,  1879,  vol.  xxxv.  p.  159. 
2  Deterraiimtion  of  the  Organic  matter  in  Potable  Waters. — Chemical 
News,  1877,  vol.  xxxvi.  pp.  26-29. 


NATUKR    OF    THE    OKGANIC    MATTER  63 

A  COMPARISON  BETWEEN  THE  RESULTS  FURNISHED  BY  1. 
THE  PERMANGANATE  OF  POTASH  PROCESS  ;  2.  THE 
WANKLYN,  CHAPMAN,  AND  SMITH  PROCESS  ;  3.  THE 
FRANKLAND    AND    ARMSTRONG  PROCESS. 

The  permanganate  of  potash  test  applied,  qualitatively.  The  Pemian- 
as  a  test  for  organic  matter,  cannot  be  compared,  in  the  ^f"^**^  °^ 

^  .  .  r  >  Potash  pro- 

results   afforded  by  it,  with  any  other  process,  for  theycessand  the 

are  thoroughly  misleading  and  unreliable.  If  the  test  isfncTArm-*^ 
employed  quantitatively,  in  the  most  approved  and  most  strong  pro- 
recent  fashion,  it  is  most  useful. 

The  permanganate  of  potash  process  has  clearly  more 
to  do  with  the  estimation  of  the  carbon  than  the  nitrogen 
of  a  water,  whilst  the  Wanklyn,  Chapman,  and  Smith 
process  is  concerned  more  with  the  evolution  of  nitrogen 
as  ammonia. 

Prof  Mallet  remarks,  "  It  is  not  easy  to  admit  the 
soundness  of  the  logic  with  which  Tidy  points  to  the 
concordance  of  the  results  obtained  by  the  permanganate 
of  potash  and  combustion  processes  and  the  disagreement 
with  both  these  of  the  results  by  the  albuminoid  ammonia 
process,  hence  apparently  inferring  that  the  two  former 
are  trustworthy  and  the  last  not  so.  He  uses  the  sum 
of  organic  carhon  and  7iitrogen  to  represent  the  results  by 
the  combustion  process,  and  as  the  carbon  forms  generally 
much  the  larger  part  of  this,  he  naturally  arrives  at  an 
agreement  with  the  results  of  the  process,  mainly  depend- 
ing on  the  oxidation  of  carbon  (the  permanganate  of 
potash  process)  and  disagreement  with  those  of  the 
process  (namely,  the  albuminoid  ammonia)  evolving 
nitrogen  as  ammonia." 

The  permanganate  of  potash  method  cannot  be  cor- 
rectly described  as  a  process,  for  it  in  reality  forms  only 
a  part  of  one.  The  indications  it  gives  should  be  con- 
sidered in   conjunction  with  those  afforded   by  an  esti- 


64 


THE    DETERMINATION    OF    THE    AMOUNT    AND 


mation  of  the  amount  of  free  and  albuminoid  ammonia, 
the  nitrogen  products  resulting  from  the  oxidation  of 
organic .  matter,  and  the  quantity  of  clilorine,  etc.  Oc- 
cupying this  subsidiary  position,  and  controlled  to  a 
great  extent  by  other  evidence,  it  exhibits  a  remarkable 
agreement  not  only  with  the  Frankland  and  Armstrong's 
process,  but  also  with  the  Wanklyn,  Chapman,  and  Smith 
process,  when  the  latter  is  associated  with  a  determination 
of  the  nitrates  and  nitrites.  The  agreement  between  the 
results  afforded  by  the  Frankland  and  Armstrong  process, 
and  the  permanganate  of  potash  method,  is  the  more 
remarkable,  because  Dr.  Frankland  has  publicly  denounced 
the  permanganate  of  potash  test  as  perfectly  useless  and 
mischievous.  The  indications  as  to  the  quality  of  a 
water  afforded  by  this  salt  are  so  corrected  by  those 
furnished  by  the  other  examinations  of  the  same  water, 
as  to  render  it  unlikely  that  any  marked  disagreement 
should  occur  between  this  permanganate  of  potash  test, 
as  carried  out  in  the  most  approved  manner,  and  the 
other  two  processes. 

The  processes,  which  have  assumed  an  antagonistic 
rivalry,  and  are  credited  with  furnishing  contradictory 
decisions,  are  the  Frankland  and  Wanklyn  methods. 
Prof  Mallet  finds  "a  good  deal  of  similarity  between  the 
figures  of  albuminoid  ammonia  and  those  for  organic 
nitrogen  by  the  Frankland  combustion  process,  but  with 
frequent  discrepancies  of  varying  extent,  such  as  prevent 
the  one  being  taken  as  the  accurate  measure  of  the 
other."  1 

Dr.  Hill  of  Birmingham  has  made  a  comparison  be- 
tween the  two  processes,  by  placing  by  the  side  of  the 
organic  nitrogen  of  Frankland's  method  the  amount  of 
nitrogen  calculated  from  the  albuminoid  ammonia  of 
Wanklyn's  method,  thus  : — 

^  Op.  cit. 


NATUEE  OF  THE  ORGANIC  MATTER 


65 


Birmingham 

Fiihlic  Water 

Sup;f 

hj. 

Date. 

Organic  nitro- 
gen by  Frank- 
land  and  Arm- 

Albd. Amm.     = 
by  the  Wank- 
lyn,  Chapman, 

and  Smith 
process. 

N. 

Ratio  of  organic 

nitrogen  to 
nitrogen  by   the 

1875. 

strong  process. 

two  methods. 

January 

•097 

'•016 

013 

7  : 

February 

•070 

'•022 

018 

4  : 

March 

•099 

•020 

016 

6  : 

April 

•064 

•014 

Oil 

6  : 

May 

•048 

•Oil 

009 

5  : 

June 

•049 

•016 

013 

4  : 

July 

•090 

•014 

Oil 

8  : 

August 

•120 

•018 

015 

8  : 

September 

•072 

•010 

008 

9  : 

October 

•070 

•014 

Oil 

6  : 

November 

•124 

•024 

020 

6  : 

December 

•080 

•014 

Oil 

7  : 

He  argues  therefrom,  that  (1)  as  the  amount  of 
nitrogen  yielded  by  the  albuminoid  ammonia  of  the 
Wanklyn  process  is  very  much  less  than  that  furnished 
by  the  Frankland  process,  which  every  one  admits,  and 
(2)  as  the  ratio  is  not  constant,  the  Wanklyn  process  is 
worthless.  ISTow  this  mode  of  comparison  appears  to  be 
unfair,  because  it  proceeds  on  the  assumption  that  Dr. 
Frankland's  process  of  water  analysis  is  a  standard  of 
accuracy,  a  pretension  which  is  open  to  considerable 
doubt,  although  as  one  for  the  analysis  of  gases  it  may 
be  most  excellent.  (Vide  Prof.  Mallet's  opinion  on 
page  61). 

Although,  then,  anything  like  a  contrast  of  numbers 
is  out  of  the  question,  a  comparison  of  the  opinions  of  a 
water  formed  according  to  the  rules  laid  down  by  the 
inventors  of  the  respective  processes,  from  a  consideration 
of  the  figures  obtained,  is  a  perfectly  feasible  project,  and 
one  likely  to  be  attended  by  useful  results.  These 
opinions  may  not  be  strictly  correct,^  but  sufficiently  so 

^  It  is  an  excellent  rule,  which  unfortunately  could  not  be  followed 
here,  to  decline  to  give  any  decision  respecting  the  nature  of  a  water  until 

F 


66  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

to  ascertain  whether  or  not  any  distinct  antagonism 
exists. 

The  following  is  a  copious  abstract  of  a  paper  entitled, 
"A  comparison  between  the  Frankland  and  Armstrong, 
and  the  Wanklyn,  Chapman,  and  Smith  processes  of 
water  analysis,"  which  was  presented  by  me  to  the  State 
Medicine  Section  of  the  British  Medical  Association,  at 
its  annual  meeting  held  in  1877,  in  Manchester,  and 
was  accompanied  by  a  table  that  contained  93  analyses 
of  waters  made  by  these  two  methods  at  or  about  the 
same  time. 

Many  analyses  of  waters  performed  by  both  the 
Frankland  and  the  Wanklyn  processes  have  been  sent 
to  me,  notably  those  from  Clayton  West,  near  Hudders- 
field,  which  I  have  not  inserted  in  the  table  of  comparison, 
simply  and  solely  because  they  were  not  made  simul- 
taneously, but  with  an  interval  of  weeks  and  months 
elapsing  between  the  periods  at  which  the  water  was 
submitted  to  the  rival  processes.  Waters  change  much 
in  the  amount  of  organic  matter  which  they  may  contain 
at  different  seasons.  The  waters  of  wells  are  greatly 
influenced  by : — (1)  height  of  the  subsoil  water,  which  is 
always  varying;  (2)  by  the  amount  of  water  that  is 
passing  through  the  subsoil  of  a  country ;  and  (3)  by 
heavy  downfalls  of  rain  or  periods  of  drought.  I  have 
many  times  found  a  water  pure  at  one  time  and  impure 
at  another,  and  this  occasional  pollution  of  a  water  is 
often  due  to  the  periodical  washing  of  filth  into  a  well 
by  heavy  rains.  The  disagreement  in  the  opinions  of 
able  analysts  respecting  the  purity  of  samples  of  water 
taken  perhaps  within  a  short  interval  of  time  from  the 
same  well  is  often  due  to  these  causes. 

furnished  with  the  fullest  information  regarding  its  source, — as,  for  ex- 
ample, the  geology  of  the  district,  depth  of  the  well,  character  of  the 
surroundings,  etc. 


NATUEE  OF  THE  ORGANIC  MATTER         67 

Dr.  Asliby,  Medical  Officer  of  Health,  made  six  analysesDr.  Ashby's 
of  different  waters,  employing  the  Wanklyn,  Chapman,!^ '^^'y^®^- 
and  Smith  process,  and  reported  certain  of  them  to  a 
sanitary  authority  as  unfit  for  use.  The  agent  of  the 
property  to  which  the  wells  belonged,  immediately,  and  in 
a  private  manner,  sent  samples  of  the  same  waters  to  an 
analyst  who  used  the  Frankland  and  Armstrong  process. 
The  opinions  formed  by  both  analysts  of  all  the  waters 
examined  by  these  two  rival  processes  coincided  in  every 
instance.  The  figures  are  unfortunately  not  obtainable, 
so  that  they  are  not  included  in  the  table,  but  that  the 
same  general  result  was  afforded  in  each  case,  and  that 
similar  conclusions  were  drawn  about  the  quality  of  these 
six  different  waters,  some  pure  and  others  impure,  is  an 
interesting  fact. 

An  examination  of  the  complete  table  shows  that  in 
only  one  single  instance  is  there  a  distinct  contradiction 
of  opinions,  and  here  the  conflict  of  views  is  readily 
accounted  for.  In  every  other  case  where  the  opinions 
are  not  identical,  the  adjectives  used  to  denote  the  de- 
cisions respecting  the  character  of  the  water  are  qualified 
by  some  adverb.  For  example,  when  an  analysis  of  a 
water  by  one  process  indicates  the  sample  to  be  "  good,' 
or  "  bad,"  an  analysis  by  the  other  process  of  the  same 
water  gives  a  verdict  of  "  very  good,"  or  "  highly  sus- 
picious," etc. 

Before  studying  the  following  table,  which  is  an 
abstract  of  the  complete  one,  it  should  be  clearly  under- 
stood that  this  comparison  is  confined  to  the  question  of 
the  quality  of  a  water  as  regards  the  amount  of  animal 
and  vegetable  organic  matter  contained  in  it.  Several  of 
the  waters  in  the  table,  as  for  example  the  last,  viz. 
"  Eaven's  Well,"  would  pass  muster  solely  from  the 
consideration  of  the  amount  of  organic  matter  contained 
therein,  but  would  be  objected  to  for  other  reasons.     The 


68 


THE    DETERMINATION    OF    THE    AMOUNT    AND 


Analyses  of  Waters  made  at  or  about  the  same 

FranJdand  and  Armstrong  jjrocess. 


Parts  per  100,000. 

Descripiion  of 
Sample. 

5  Z 

6  3 

If 

0-= 

1   1.2 
111 

O 

_c3 

C 

^  ci  K 

s 
s 

o 

Opinion. 

Deeply        bored 
well       .     .     . 

•229 

•055 

4^2 

•299 

297 

Good.* 

Water    used    for 
the  washing  of 
milk    cans    at 
an      Islington 
Daily    . 

1-820 

•710 

2-5 

•120 

•400 

7-10 

(  Horribly 
1      polluted. 

AVest   Middlesex 
Water      Com- 
pan}^  January 
1873      .     .     . 

•341 

•034 

10-0 

•001 

•266 

1^9 

Indifferent. 

Surface  spring    . 

•128 

•027 

4^7 

•004 

■471 

6-92 

Suspicious.* 

Well  water    .     . 

•177 

•017 

10-0 

■004 

•184 

2^72 

Good.* 

Deeply        bored 
well      .     .     . 

•093 

•009 

11-4 

•241 

3^61 

Good. 

Water  from  deep 
well       .     .     . 

•110 

•062 

1-9 

•002 

•253 

3^1 

Good.* 

Well   in   Kowe's 
Square,  Cardiff 

•181 

•037 

5^0 

3  ■76 

15^5 

Bad.t 

Artesian  Well  of 
Maldou  Water 
AVorks  .     .     . 

•148 

•029 

5^1 

•110 

35  ■S 

Good.t 

"Raven's  Well" 
(deep)   . 

•261 

•023 

11-3 

•001 

■007 

9-9 

Prett-y  Good. 

NATUEE  OF  THE  OEGANIC  MATTER 


69 


time  BY  THE  Feankland  and  Wanklyn  Peocesses. 

WanMyn,  Chapman,  and  Smith  2}rocess. 


MlLLIORASlME 

PER  Litre. 


Grains  per 
Gallon. 


1-10 


•04 

•04 


•04 


•04 

•08 

•08 
•12 
•09 

•06 

•10 
•1-2 

.•13 
•12 
•04 
•02 
•11 
•01 

•08 


•17 
2^64 

•67 

7^40 

Trace. 

•07 

•06 


2-0 

5-1 

1^4 
4^8 
1^9 

2-1 
10^81 
10-81 
11-80 

25-7 
25  •o 
25  •o 


Opiniox. 


•00       7^3 


Vei-y  good. 


Horribly 
polluted. 


Not  first  rate. 
Suspicious. 
Pretty  good. 

Good. 

/  Moderately 
I     good. 
Bad.7 

Bad.S 

Bad.  77 

Good.X 

Good.w 

Bad.x 

Good./3 

Pretty  good. 


Remarks. 


"■Opinion  of  the  analyst,  Dr. 
G.  Brown. 


/'Analyses  made  by  Dr. 
i  Bartlett,  who  states  that 
<  29  cases  of  typhoid  fever 
I  occurred  amongst  the 
\^     customers  of  the  dairy. 


+  Opinion    of    the   analyst, 
Dr.  Frankland. 

7  Opinion   of  the  analyst, 

Mr.  Thomas. 
3  Opinion    of    the   analyst, 

Mr.  Scott. 
7)  Opinion    of    the   analyst, 

ilr.  Wanklyn. 
X  Opinion   of   the   analyst, 

Dr.  Tidy, 
w  Opinion    of  the   analyst. 

Dr.  Whitmore. 
X  Opinion  of  Messrs.  Hassall 

andHehner,  theanalj-sts. 
/3  Opinion  of  Dr.  Cornelius 

Fox,  the  analyst. 
N.B. — The  sample  received  by  Has- 
sall and   Hehner  was  jirobably 
obtained  from  a  dirty  cistern. 


70  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

water  was  condemned  because  of  its  large  amount  of  saline 
matter  and  its  excessive  hardness. 

A  very  careful  study  of  the  two  processes,  and  the 
comparative  results  afforded  by  them,  lead  me  to  the 
following  conclusions : — 

Conclusions.  1.  In  ouc  iustancc  only  out  of  99  analyses,  details 
of  93  of  which  are  in  my  possession,  is  there  a  distinct 
conflict  of  opinion,  and  in  this  exceptional  instance  the 
divergence  in  the  results  obtained  is  easily  explained. 

2.  The  opinions  do  not  in  a  great  many  instances 
coincide  exactly,  but  the  adjectives  denoting  them  are 
modified  by  some  qualifying  adverb. 

3.  When  the  results  of  analyses  made  by  the  two 
processes  at  or  about  the  same  time  do  not  at  all  agree, 
the  divergence  is  generally  due  to  the  neglect  on  the 
part  of  those  who  practise  the  Wanklyn,  Chapman,  and 
Smith  process,  to  estimate  the  amount  of  nitrates  and 
nitrites,  and  to  be  guided  by  the  evidence  thus  afforded. 

4.  The  results  are  not  concordant  unless  the  analyses 
are  performed  upon  the  same  water  at  the  same  tune. 

5.  A  really  bad  water  would  not  be  likely  to  escape 
detection  by  either  process  if  the  nitrates  and  nitrites 
are  always  estimated. 

6.  The  danger  of  the  delivery  of  contradictory 
opinions  respecting  any  given  sample  of  water,  lies 
chiefly  in  the  fact  that  Frankland's  process  gives  higher 
results  than  Wanklyn's  method,  so  that  a  water  pro- 
nounced as  just  passable  by  the  latter  process  might  be 
condemned  by  the  former. 


NATUEE  OF  THE  ORGANIC  MATTER 


71 


VALUE  OF  THE  FEANKLAND  AND  ARMSTRONG,  WANKLYN, 
CHAPMAN,  AND  SMITH,  AND  THE  QUANTITATIVE  FOR- 
CHAMMER  PERMANGANATE  OF  POTASH  PROCESSES  IN 
THE    DETECTION    OF    DANGEROUS    POLLUTIONS. 

An  investigation  was  carried  out  during  the  years 
1880-81  by  Dr.  Cory,  at  the  instance  of  the  Medical 
Department  of  the  Local  Government  Board,  to  determine 
whether  chemistry  was  able  to  distinguish  between  water 
contaminated  by  common  or  specifically  infected  filth. 
The  experiments  lead  to  conclusions  of  rather  a  startling 
character  which,  unless  faced  and  dealt  with,  may  diminish 
the  faith  of  water  analysts  in  their  powers  of  diagnosis.  •■• 
"Waters  were  polluted  with  weighed  portions  of  excrement 
from  a  case  of  typhoid  fever  and  from  a  man  in  perfect 
health,  and  comparisons  were  instituted.  On  page  137 
of  the  Eeport  is  a  table  and  comment  on  the  same,  of 
which  the  followinff  is  an  abstract. 


IiK^'ements  indicated  by- 
analysis  to  have  been 
gained  by  additions  of 
known  quantities  of 
material  to  a  gallon  of 
water. 


Polluted 
with  "OS 
grni.  of 
typhoid 
stool. 


Polluted 

Polluted 

with  -05 

with    -1 

grm.    of 

grm.    of 

healthy 

typhoid 

stool. 

stool. 

Polluted 
with  •! 
grm.  of 
healthy 
stool. 


Chemical  Increments  in  grs.  per  gal. 


Volatile  matters 
Ammonia 
Alb.  ammonia 


1-12 
•0004 
•0020 


.•96 
•0015 
•0059 


•12 

•0006 
•0048 


1-e 


•0026 
•0216 


"  The  addition  of  the  typhoid  stool  gave  to  water  far 
less  indication  of  pollution  than  was  given  by  an  equal 
quantity  of  healthy  stool." 

(a)  As  regards  this  table,  it  is  worthy  of  note  that  the 

1  The  inconclusive  nature  of  this  Report  is  described  in  detail  in  a 
paper  entitled  "Remarks  on  the  Examination  of  Water  for  Sanitary 
Purposes,"  read  before  the  Socy.  of  Med.  Officers  of  Health  on  February 
16,  1884,  by  C.  E.  Cassal  and  Dr.  Whitelegge. 


72 


THE  DETERMINATION  OF  THE  AMOUNT  AND 


healthy  man  was  fed  during  four  days  previous  to  the 
experiiaent  on  a  much  larger  amount  of  soluble  nitrogen- 
ous organic  matter  than  the  patient  with  whom  he  was 
compared,  hence  the  striking  difference  observable  in  the 
amount  of  volatile  matters,  which  were  nearly  twice  as 
much  in  the  healthy  as  in  the  typhoid  case. 

(b)  The  proportion  of  the  highly  carbonaceous  matter 
of  the  biliary  discharges  to  nitrogenous  matter  may  have 
been  greater  in  the  one  case  than  in  the  other. 

(c)  The  solubility  of  constituents  of  stools  was  not 
shown  to  be  alike  in  both  cases. 

Again  we  are  confronted  on  page  142  with  a  table,  of 
which  the  following  is  an  abstract : — 


Umpol 

Lar 

Dupre,rr 

LUTED  Sa 

«PLES. 

er. 
Vanklyn. 

Poll 

Lamlae 
in  the  pi 
of  solub 
typhoid 

UTED  Samples. 

ibetli  wal 

th  water  polluted 
oportion  of  '21  gr. 
e  solid  matter  of 
stool  to  each  gall. 

ankland,^ 

Dupre,Frankland,Wanlclyn. 

Oxygen    absorbed   from 
Permanganate 
Ammonia  .... 
Alb.  Ammonia     .     . 
Organic  Carbon    .     . 
Organic  Nitrogen 

Grains  per  Gallon. 

Grains  per  Gallon. 

•2415 
■0011 
•0090 

•2114 
•0371 

•0014 
•0056 

•2512 
•0016 
•0100 

•2205 
•0399 

■0007 
•007 

The  result  is  in  accordance  with  our  previous  know- 
ledge as  to  the  impossibility  of  distinguishing  between 
healthy  and  specific  contamination  of  drinking  water. 
The  three  different  processes  supply  general  indica- 
tions, which  require  to  be  checked  by  other  evidence. 
Whilst  the  albuminoid  ammonia  process  furnishes  us 
with  ammonia  evolved  by  a  portion  only  of.  the  organic 
matter,  and  the  oxygen  process  only  records  the  oxygen 
used  up  by  a  part  of  the  organic  matter,  the  combustion 
process  yields  the  carbon  and  nitrogen  contained  in  the 


NATURE  OF  THE  ORGANIC  MATTER         73 

residue  of  a  water  to  the  exclusion  of  that  lost  during 
the  evaporation  of  the  same. 

Duplicates  of  the  samples  of  water  polluted  by  typhoid 
and  healthy  excrements  were  examined  microscopically, 
and  each  sample  that  was  thus  examined  was  found  to 
contain  "crowds  of  bacteria" — a  fact  of  itself  most  damag- 
ing to  the  character  of  any  drinking  water.  I  do  not 
remember  ever  to  have  seen  a  natural  water  containing 
"  crowds  of  bacteria"  in  each  field  of  the  microscope  that 
did  not  present  other  evidence,  sufficient  when  combined 
to  condemn  it  as  a  water  supply.  The  inquiry  affords  a 
confirmation  of  the  accuracy  of  the  opinion  expressed  by 
me  for  the  last  eight  or  ten  years,  that  a  sole  reliance  on 
the  results  afforded  by  these  processes  for  the  detection  of 
the  carbon  and  nitrogen  (apart  from  subsidiary  analytical 
e^ddence,  in  which  respect  the  Medical  Officer  of  Health's 
method  differs  from  all  others)  often  leads  to  mistakes. 
It  does  not  follow  that,  because  chemical  analysis  might 
have  failed  to  detect  the  accidental  poisoning  by  a  workman 
of  a  vast  quantity  of  pure  water  by  specifically  infected 
matter,  as  at  the  Caterham  and  Eedhill  outbreak  of  enteric 
fever  (of  which  failure  no  proof  was  afforded^),  therefore 
water  analysis  is  useless.  In  ninety-nine  cases  out  of  one 
hundred  (1)  such  specifically  infected  matter  is  introduced 
into  a  well  in  conjunction  vnth  other  animal  organic  matter; 
(2)  the  presence  of  animal  organic  matter  indicates  an  open 
door  or  channel  for  the  chance  entrance  of  specific  poison ; 
and  (3)  as  a  matter  of  experience  it  may  be  confidently 
asserted  that,  as  a  rule,  minute  quantities  of  specifically 
infected  matter  do  not  alone  gain  admission  into  well 
water.  If  the  "  filth  diseases "  are  propagated  either 
through  the  instrumentality  of  living  organisms  with  their 

■^  The  author  possesses  evidence  ■which  tends  to  show  that  a  great 
change  did  take  place  in  the  amount  of  the  minevcd  constituents  of  the 
water. 


74  THE    DETERMINATION    OF    THE    AMOUNT    AND 

power  of  unlimited  self-multiplication,  or  by  animal  poisons, 
associated  each  with  its  characteristic  organism,  it  is 
probable  that  a  large  amount  of  organic  matter  in  a  water 
is  more  objectionable  than  a  small  amount,  as  furnishing 
more  material  and  conditions  suitable  for  the  develop- 
ment of  noxious  as  well  as  harmless  organisms.  So  far 
as  regards  the  bacillus  anthracis,  it  has  been  shown  ^ 
that  this  micro-organism  does  not  flourish  in  pure  water. 
Its  food  supply  is  used  up  within  a  few  hours,  and  the 
water  which  has  been  infected  with  it  soon  loses,  when 
applied  to  a  suitable  culture-medium,  its  infective  property. 
The  duration  of  infectivity  in  purposely  infected  water 
was  found  to  vary  with  the  proportion  of  nutrient  animal 
matter  contained  therein.  As  Tiemann  and  Preusse  have 
well  pointed  out,^  although  an  impure  water  is  not  neces- 
sarily pernicious,  a  polluted  water  is  more  likely  to  contain 
disease  ferments  than  a  pure  one. 

9. — Koch's  Biological  Method. 

The  determination  of  the  amount  of  organic  and  mineral 
matters  contained  in  a  water  may  be  usefully  supple- 
mented by  an  estimation  as  to  the  number  and  nature  of 
the  micro-organisms  in  it,  which  supplies  us  with  informa- 
tion that  a  chemical  examination  does  not  afford. 

Bacteriological  researches  as  to  the  nature  and  life- 
history  of  micro-organisms  belong  to  laboratories  devoted 
to  biological  investigations,  but  the  power  of  ascertaining 
whether  their  number  in  a  water  is  beyond  the  normal 
amount  is  within  the  reach  of  the  health  officer.  The 
difficulties  which  attend  the  employment  of  the  following 
adaptations  of  Koch's  biological  process  to  water  examina- 
tion are  involved  in  the  necessity  of  the  expenditure  of 
a  great   deal   of  time,  a  close  attention  to  details,  the 

1  Eeports  on  London  Water  Supply,  for  June  and  August,  1886,  by 
Mr.  W.  Crookes  and  Drs.  Odling  and  Tidy. 

^  Chemical  Neivs,  January  16,  1880,  pp.  30,  31. 


NATUEE  OF  THE  ORGANIC  MATTER        75 

observance  of  scrupulous  cleanliness,  and  the  \vant  of  a 
tlioroughly  satisfactory  mode  of  numerically  distinguishing 
waters  of  similar  organic  impurity  one  from  another. 
The  first  to  be  described  is  a  qualitative  examination,  Dr.  Jiuter's 
which  has  given  some  very  striking  results  in  the  hands  ^^'^'^' 
of  Dr.  Muter.^  Obtain  some  good  fresh  gelatine^  in  very 
thin  lamince.  Thoroughly  dessicate  it  at  the  highest 
possible  temperature,  and  enclose  it  in  a  carefully 
cleansed  and  dried  bottle.  Then  100  c.  c.  of  redistilled 
water  is  well  boiled  in  a  clean  flask,  the  mouth  is  closed 
by  cotton  wool,  and  the  whole  is  allowed  to  cool  to  90° 
r.  Four  grammes  of  the  gelatine  and  two  centi- 
grammes of  sodium  phosphate  are  now  placed  in  the  flask, 
and  the  mouth  having  been  again  closed,  agitation  is 
persisted  in  until  entire  solution  takes  place.  A  fresh 
egg  is  now  broken,  and  a  little  of  the  white  is  added  to 
the  contents  of  the  flask,  which  are  then  boiled  and 
filtered  through  a  paper  sterilized  by  heat ;  2  5  c.  c.  of  the 
filtered  liquid  are  then  mixed  with  an  equal  volume  of 
the  suspected  water  in  a  tube  closed  by  cotton  wool,  and 
kept  at  a  temperature  of  60°  to  70°  F.  A  comparison 
tube  is  also  set  up  with  redistilled  and  previously  boiled 
water.  With  really  infected  water,  a  cloudy  layer  of 
bacteria  will  form  within  a  comparatively  short  space  of 
time,  and  the  gelatine  will  liquefy  from  the  surface  down- 
wards, and  will  disengage  putrid-smelling  inflammable  gases. 

TJie  late  Dr.  Angus  Smith's  adaptation  of  Koch's  Method  of 
Water  Examination.^ 

A  5  per  cent  solution  of  the  thin  leaf  gelatine,  which  Dr.  a. 
solution  melts  at  about  80°  F.,  is  clarified  by  filtration  or  adaptation. 

^  Analyst,  September  1885. 

^  French  gelatine,  sold  in  thin  transparent  sheets,  of  the  best  quality,  is 
preferred  in  biological  experiments. 

^  Second  Keport  under  the  River  Pollution  Prevention  Act  of  1876,  to 
the  Local  Government  Board,  "On  the  Examination  of  Waters." 


76 


THE    DETERMINATION    OF    THE   AMOUNT    AND 


by  fresh  albumen.  Of  tliis  solution  2  5  c.  c.  are  placed  in  a 
test  tube  and  then  mixed  with  25  c.  c.  of  the  water  to 
be  examined,  and  kept  for  some  minutes  at  that  tempera- 
ture; but  much  smaller  quantities  are  frequently  sufficient. 
The  tubes  in  which  the  experiments  are  made  are  about 
8  inches  long  and  1  inch  in  diameter,  with  stoppers  of 
cotton  wool  only.  After  the  mixture  cools  it  becomes  solid 
around  any  organisms  which  may  be  present,  transparent 
spheres  forming  which  contain  active  and  inactive  bacteria. 
Distilled  water,  if  examined,  exliibits  no  change,  but  other 
waters  display,  according  to  their  purity,  a  greater  or  less 
number  of  these  spheres  or  colonies,  which  may  be 
counted.  A  number  of  very  minute  white  dots  are 
sometimes  "\dsible,  and  seem  to  indicate  the  number  of 
points  of  vitality  in  the  w^ater.  Sugar  and  phosphate  of 
soda  were  in  some  experiments,  by  Dr.  A.  Smith,  added  to 
the  gelatine,  both  together  and  separately;  but  gelatine 
alone  seemed  to  give  clearer  and  simpler  results.  He  writes, 
"  Of  all  the  forms  of  change  in  these  tubes,  that  which 
seems  to  be  connected  with  the  most  offensive  waters  is 
the  liquefying  of  the  surface.  The  number  of  points  of 
activity  one  naturally  considers  a  measure  of  impurity." 

Dr.  Percy  FranUancVs  adaijtation  of  Koch's  method  of 
Water  Examincdion} 


Dr.  P. 

"Composition  op  Medium  and  M 

ODE    OP    Jr'REPARATION 

Frankland's 

Lean  meat    .... 

1  lb. 

adaptation. 

Gelatine       .... 

150  grms. 

Peptone  (solid) 

•        10     „ 

Common  salt 

1      „ 

Di'stilled  water 

1  litre. 

^  "New  aspects  of  Filtration  and  other  methods  of  Water  treatment : 
The  gelatine  process  of  "Water  examination."  A  paper  originally  presented 
to  the  Socy.  Chem.  Industry,  but  since  reprinted. 

'  Koch  employs  100  grms.,  which  has  been  found  insufficient,  as  it 
liquefied  at  as  low  a  temperature  as  68°  Y. 


NATUKE  OF  THE  OEGANIC  MATTER 


77 


The  meat  is  finely  minced  and  infused  with  a  half  litre 
of  cold  distilled  water  for  1  to  2  hours,  the  solid  part 
being  then  strained  off  through  linen.  The  gelatine  is 
allowed  to  soak  in  the  other  half  litre  of  water,  and  to 
this  the  extract  of  meat  is  added.  The  whole  is  now 
heated  until  the  complete  solution  of  the  gelatine  has 
taken  place,  the  peptone  and  salt  being  then  added  and 
allowed  to  dissolve.  This  liquid  exhibits  a  distinctly 
acid  reaction,  which  must  be  carefully  neutralized  by 
means  of  carbonate  of  soda.  The  neutralized  liquid  is 
then  clarified  by  beating  into  it  the  contents  of  two  or 
three  eggs,  along  with  the  broken  shells,  the  whole  being 
briskly  boiled  for  a  few  minutes.  The  coagulated 
albumen  rises  to  the  surface  and  carries  with  it  the  other 
solid  particles  suspended  in  the  liquid.  On  then  strain- Filtration  of 
ing  through  linen,  a  fairly  clear  liquid  is  obtained,  which  ™^g*'^^^^' 
is  finally  clarified  by  passing  through  filter-paper  placed  gelatine 

medium. 


Fig.  4. 
Glass  funnel  surrounded  by  Copper  Jacket  for  iiltering  Gelatinized  Meat  Infusion. 

in  a  funnel  provided  with  a  hot  water  jacket,  the  filtrate 
being  rejected  until  it  runs  perfectly  clear  and  limpid. 


78 


THE  DETERMINATION  OF  THE  AMOUNT  AND 


The  filtrate  sets  on  cooling  to  a  yellowisli  brown  trans- 
parent jelly.  Whilst  still  liquid  it  is  poured  into  clean 
test  tubes,  the  quantity  which  I  employ  in  each  tube 
Sterilization  being  cxactly  7  c.  c.  The  test  tubes  are  tightly  plugged 
with  cotton  w'ool  and  then  at  once  sterilized  by  steaming 
them  for  half  an  hour  on  three  consecutive  days  in  a 
vessel  made  expressly  for  the  purpose,  and  the  con- 
struction of  which  is  shown  in  the  accompanying  figure. 


by  steam. 


^^ 


? 


Steaming  Apparatus 
and  Steamer  to  fit 
in  ditto. 


t.  Thermometer. 


=^ 


Tubes  prepared  and  sterilized  in  this  manner  I  have 
found  to  remain  unchanged  for  an  indefinite  period  of 
time."  ^ 

1  If  it  is  desired  to  avoid  the  trouble  of  preparing  sterilized  meat 
peptone  gelatine,  it  can  be  purchased  from  Dr.  H.  Rohrbeck  of  Berlin  in 
test  tubes  or  flasks. 


NATUKE    OF    THE    OEGANIC    MATTER 


■9 


Collection  of  Samjjles  of  Water. — Glass  stoppered  collection  of 
bottles  of  about  70  c.  c.  capacity  are  cleansed,  rinsed  ^^™^'^^' 
with  distilled  water,  dried  and  kept  in  an  air  bath  at 
from  302°  F.  to  356°  F.  for  at  least  3  hours.  In 
taking  a  sample  the  outside  of  the  bottle  should  be 
rinsed  in  the  water  before  removing  the  stopper,  and 
exposure  to  the  air  be  reduced  so  far  as  possible  to  a 
minimum.  The  mouth  of  the  bottle  should  not  be 
allowed  to  come  into  contact  with  the  tap.  In  collect- 
ing samples  from  ponds  or  rivers,  the  stopper  should 
not  be  removed  until  the  bottle  is  completely  immersed 
in  the  water,  and  should  be  replaced  whilst  still  below 
the  surface. 

Sterilization  of  A'pimratus. — It  is  necessary  to  steri- sterilization 
lize   every   article   that    is    used    in    these    experiments.  ^^^°*^""" 


Fig.  C. 

Hot  air  chamber  for  sterilizing  Pipettes,  Glass  Plates  in  metal  box,  cotton  wool,  etc. 
t.  Thermometer. 

Dr.  Klein  states^  that   cotton  wool   should   be   exposed 
in  a  loose  state  in  a  hot  air  chamber  to  a  temperature 

^  Micro-onjanisms  and  Disease. 


80  THE    DETERMINATIOX    OF    THE    AMOUNT    AND 

as  high  as  from  266°  F,  to  302°  F.,  for  several  succes- 
sive hours,  for  several  successive  days,  and  that  it  ought 
to  be  just  singed.  Glass  apparatus  is  sterilized  by 
exposure  in  the  hot  air  chamber  for  3  hours  to  a  tem- 
perature of  from  302°  F.  to  356°  F.,  and  by  washing  in 
sterilized  distilled  water  or  a  2  per  cent  solution  of 
corrosive  sublimate. 

Tlie  Examination  of  SamiJle,  which  should  be  performed 
as  soon  as  possible  after  collection,^  must  be  violently 
shaken  to  ensure  an  even  distribution  of  the  organisms 
throughout  the  water.  At  this  stage  Koch  determines  ^ 
approximatively,  by  making  a  cover  glass  preparation 
{vide  page  161),  the  number  of  micro-organisms  present,  in 
order  to  judge  as  to  the  quantity  of  the  water  under 
examination  which  should  be  used.  "  If  on  microscopic 
examination  one  bacillus  be  detected  in  each  '  field,'  one 
drop  of  the  water  will  contain  many  hundreds,  and  less 
than  1  c.  c.  should  be  taken  for  mixing  with  the  gelatine. 
On  the  other  hand,  should  several  '  fields '  have  been 
examined  without  detecting  a  bacillus,  then  1  c.  c.  of  the 
water  should  be  taken."  It  is  better  to  take  too  little 
water  than  too  much,  because  in  the  latter  case  the 
colonies  are  so  crowded  that  it  is  almost  impossible  to 
count  them.  A  tube  of  the  sterilized  gelatine  peptone 
medium,  melted  by  placing  it  in  water  not  heated  above 
86°  F.,  is  opened  after  first  singing  the  external  portion 
of  the  cotton  wool  plug.      Into  it  one  or  more  drops  ^ 

1  In  a  receut  number  of  the  Chemical  Keics,  Dr.  T.  Leone  is  reported 
to  have  found  that  the  pure  spring  -R-ater  which  supplies  Munich  enters  it 
Avith  5  organisms  in  each  1  c.  c,  which  on  standing  24  hours  increased  to 
100,  in  2  days  to  10,500,  and  on  the  5th  day  to  half  a  million,  this 
multiplication  occurring  at  a  temperature  of  from  57  "2  to  64 '4°  F. 

2  The  Biological  Examination  of  "Water  as  carried  out  in  the  Reichs 
Gesundheits  Amt.  Berlin,  vide  paper  by  Professor  Warden  in  Chemical 
News,  July  31,  1885. 

3  It  is  necessary  .to  ascertain  how  many  drops,  delivered  by  the  pipette 
employed,  form  1  c.  c,  as  drops  differ  so  much  in  size. 


NATUEE  OF  THE  OEGANIC  MATTER        81 

(according  to  the  quantity  it  has  been  predetermined  to 
employ)  of  the  water  under  examination  is  transferred 
by  means  of  a  graduated  pipette  (which  has  been  pre- 
viously sterilized  in  .a  tin  box  by  heating  it  from  302°  F. 
to  356°  F.)  and  the  water  and  gelatine  are  rapidly  mixed 
(carefully  avoiding  the  formation  of  bubbles)  by  agitation 
in  the  tube,  which  is  held  in  a  slanting  position  to  prevent 
the  entrance  of  dust. 

Arrangement  for   recejition  of  Glass   Plate. — A    soup  Plate  cuiti- 
plate,  in  which  rests   a   very   short -legged  tripod,  which  ^ 


Ftg.  7. 

Apparatus  employed  for  Plate  Cultivations.    (After  Crookshank.) 

Tripod  stand  ;  Glass  dish,  filled  with  cold  or  iced  water ;  Sheet  of  Plate-glass ;  Spirit 

Level,  and  Glass  Bell. 

supports  a  glass  plate  protected  by  a  glass  cover,  having 
with  its  contents  been  rinsed  with  boiled  redistilled 
water  immediately  before  use,  is  by  the  help  of  a  spirit 
level  rendered  perfectly  horizontal,  and  a  little  of  the 
same  sterilized  distilled  water  is  poured  into  it  so  as  to 
form  a  seal  between  the  outer  and  inner  air.  Dr.  Edgar 
Crookshank  recommends  ^  that  the  solidification  of  the 
liquid  nutrient  jelly  should  be  hastened  by  placing  the 
glass  plate  on  a  slab  of  glass  covering  a  vessel  full  to  the 
brim  with  cold  water,  which  may  be  iced  in  warm  weather. 

^  Introduction  to  Practical  Bacteriology. 
G 


82 


THE    DETERMINATION    OF    THE    AMOUNT    AND 


Prof.  Warden  states  that  this  arrangement  may  be 
improved  by  placing  the  water -receiver  in  an  empty 
shallow  vessel  into  which  it  fits  loosely,  and  in  which  it 
is  supported  on  three  pieces  of  cork.  This  outer  vessel 
which  rests  on  the  tripod  serves  to  receive  the  overflow 
water  and  any  moisture  which  may  condense  on  the  sides 
of  the  iced  water -receiver.  A  sterilized  glass  plate  is 
now   withdrawn   (the   future    upper   surface   being   held 


Fig.  S. 
Inculjator,  with  a  gas  regulator  (a)  in  air  chamber.     (After  TVoodhead  and  Hare.) 

downwards)  from  a  metal  box  in  which  it  has  been 
sterilized,  and  is  placed  on  the  levelled  plate,  and  the 
contents  of  the  test  tube  are  poured  on  to  it.  Koch  and 
others  ad^dse  that  the  gelatine  be  evenly  spread  over  the 
plate  by  the  help  of  a  sterilized  glass  rod  so  as  to  form  a 
square.  As  soon  as  the  gelatine  has  set  on  the  plate 
it  is  at  once  removed  in  its  dish  into  an  incubator,  main- 
tained at  a  temperature  of  from  68°  F.  to  77°  F.     Koch 


NATURE    OF    THE    ORGANIC    MATTER  83 

recommends  that  the  glass  plate  after  solidification  of  the 
gelatine  should,  instead  of  being  placed  in  an  incubator, 
be  transferred  to  the  glass  bench  of  the  "  damp  chamber," 
where  in  the  course  of  a  day  or  two,  according  to  the 
temperature  of  the  room  which  should  be  from  60°  F.  to 
65°  E.,  the  colonies  will  develop.  The  "damp  chamber  "  Damp 
consists  of  a  shallow  glass  dish,  a  covering  bell,  and  glass  *^  ""'" 
rack,  all  of  which  have  been  thoroughly  cleansed  and 
washed  with  a  solution  of  corrosive  sublimate  (1  part  to 
1000  of  water).  The  bottom  of  the  glass  dish  is 
covered  with  two  or  more  layers  of  filter -paper  cut  to  the 


Damp  Chamber  for  Plate  Cultivations.    (After  Crookshank.) 
It  contains  a  glass  rack  on  which  rest  gelatine  glass  plates. 

size,  taking  care  that  it  does  not  project  beyond  the  edge  of 
the  covering  bell.  The  vertical  portion  of  the  glass  cover 
is  lined  internally  by  some  with  a  circular  strip  of  blotting- 
paper  to  prevent  any  drops  of  condensed  moisture  from 
falling  on  the  plates.  All  of  the  blotting  or  filter-paper 
is  moistened  with  the  corrosive  sublimate  solution.  Dr. 
P.  Frankland  writes,  "  The  period  of  incubation  generally 
varies  from  3  to  5  days,  but  sometimes  it  is  continued 
for  a  longer  period  of  time,  to  make  sure  that  all  the 
organisms  present  have  had  a  due  opportunity  of  develop- 
ment." The  gelatine  plates  are  daily  inspected  during  the 
period  of  incubation,  without  removing  the  glass  cover,  so 
that  the  progress  of  the  colonies  derived  from  the  in- 
dividual organisms   may  be  watched ;   when  these  have 


84  THE    DETEEMINATION    OF    THE    AMOUNT    AND 

reached  such  dimensions  that  they  are  distinctly  visible 
to  the  naked  eye,  and  before  the  contours  of  different 
colonies  have  begun  to  coalesce,  the  plates  are  withdrawn 
for  examination.  The  colonies  are  counted  with  the  aid 
of  a  strong  hand -lens,  the  more  doubtful  ones  being 
further  examined  by  means  of  a  simple  microscope.  In 
Enumera-  Order  to  arrive  at  an  accurate  conclusion  with  respect  to 
the  number  of  colonies,  it  is  necessary  that  they  should 
all  be  counted  individually ;  but,  in  cases  in  which  the 


tion  of 
colonies, 


Fig.  10. 

Apparatus  for  estimating  the  Number  of  Colonies  in  a  Plate 

Cultivation.    (After  Grookshank.) 

The  ruled  plate  di^aded  into  centimetre  squares,  some  of  which  are  suh-divided 

into  ninths,  is  so  arranged  as  to  cover  the  gelatine  plate  without  touching  it. 

colonies  are  very  numerous,  an  estimate  of  the  total 
number  may  be  formed  by  placing  the  gelatine  plate 
on  or  beneath  a  second  glass  plate  ruled  in  squares, 
the  arrangement  resting  upon  a  black  ground.  The 
colonies  present  in  a  few  of  these  squares  are  counted 
and  then  multiplied  accordingly.  A  substitute  for  this 
appliance  is  made  by  ruling  with  a  white  lead-pencil,  on 
a  piece  of  dull  black  paper  pasted  on  cardboard,  a  square 
divided  by  horizontal  and  vertical  lines  into  100  centi- 
metre squares,  several  of  which  may  be  sub-divided  by 
two  horizontal  and  vertical  lines  into  nine  smaller  squares. 
Dr.  P.  Frankland  found  that  if  boiled  distilled  water  is 
examined,  the   gelatine  plates  almost   invariably  remain 


NATURE  OF  THE  ORGANIC  MATTER         85 

unchanged.       Koch    considers    that    3    colonies    is    the 
average  obtained  with  distilled  water. 

The  following  observations  on  the  Metropolitan  Waters 
are  interesting  as  an  earnest  of  what  this  method  is 
capable : — 


Micro-organisms  in  1  Cub.  Cent,  of  Metropolitan  Waters,  1885. 

Jan. 

Feb. 

Mar. 

May. 

June. 

Se'pt. 

Oct. 

Nov. 

Dec. 

River  Thames  at — 
Hampton^    .     . 
Chelsea    .     .     . 
West  Middlesex 
Southwark   .     . 
Grand  Junction 
Lambeth      .     . 

River  Lea  at — 
Chingord  MilP 
New  River    .     . 
East  London 
Deep  Wells. 

Kent  — (Well      at 
Deptford)     .     . 
Supply    .     .     . 

"s 

2 

13 

382 

10 

"7 
25 

16 

23 
16 
26 

57 
5 

'7 
39 

41 

10 

7 
246 

28 
69 

95 
17 

"'9 

14 
3 

24 
3 

30 

"3 
121 

20 

155 
22 

21 

6 

26 

81 
26 
47 
18 
38 

27 
22 

1644 

13 

2 

18 

43 

103 

"3 
29 

'i"4 

714 
34 
2 
24 
40 
26 

2 
53 

6 

18 

18662 

3 

5 

32 

40 

26 

9542 

n 

14 
8 

"9 

15 

73 

134 

124 

18 
317 

5 

7 

Micro- 
organisms 
in  London 
waters. 


The  water  of  the  Kent  Company  leaves  the  well,  as  is 
seen,  almost  wholly  destitute  of  organic  life,  and  the  few 
organisms  which  it  does  contain  are  almost  certainly  im- 
ported into  it  en  route  to  its  supply. 

I  would  recommend  the  adoption  of  Dr.  Angus  Smith's 
method  to  those  who  have  but  little  time  to  expend  in  such 
examinations.  To  those  who  have  had  some  experience  in 
the  observation  of  micro-organisms  I  would  commend  Dr. 
P.  Frankland's  method,  with  the  modifications  of  others, 
which  is  undoubtedly  the  best  that  has  been  devised. 

^  These  iigures  represent  results  obtained  by  the  examination  of  the 
waters  above  the  intakes  of  the  Water  Companies,  and  show  the  efiect  of 
the  storage  and  filtration  of  the  waters  which  they  supplj'. 

2  Heavy  floods  during  November. 


86         the  determination  of  the  amount  and 

10.  The  Estimation  of  Dissolved  Oxygen 
IN  Watee. 

The  old  custom  of  judging  of  the  purity  of  a  water  by 
the  amount  of  its  dissolved  oxygen  has  recently  been 
revived.  The  question,  however,  as  to  whether  the 
quantity  of  oxygen  bears  any  constant  ratio  to  the 
organic  impurities  is  an  open  one,  and  requires  elucidation. 
As  water  becomes  more  and  more  contaminated  with 
putrescent  organic  substances,  the  quantity  of  dissolved 
oxygen  in  it  rapidly  diminishes.  Dr.  Odling  has  shown 
that  at  a  temperature  of  59°  F.  three  volumes  of  oxygen 
are  dissolved  in  100  volumes  of  water,  and  that  an 
increase  of  solubility  is  obtained  by  a  reduction  of  tem- 
perature. At  the  summer  temperature  of  70°  F.  water 
contains  1"8  cub.  in.,  and  at  the  winter  temperature 
of  45°  F.  2" 2  cub.  in.  of  oxygen  per  gallon.  The 
processes  for  the  determination  of  the  dissolved  oxygen 
are  all,  with  one  exception,  beyond  the  reach  of  the 
Medical  Officer  of  Health,  requiring  complex  apparatus 
and  consuming  more  time  than  he  can  afford.  The 
method  described  in  A.  Proust's  TraiU  cV Hygiene,  p.  427, 
is  the  only  one  which  can  be  suggested  as  at  all  suitable 
for  him,  if  he  desires  to  launch  out  into  the  unknown  on 
this  new  branch  of  water  analysis.  A  copy  of  a  trans- 
lation of  the  manuscript  notes  of  M.  Gerardin,  who  with 
Schiitzenberger  invented  this  process,  have  been  kindly 
sent  to  me  by  Mr.  J.  W.  Slater. 

A  solution  of  the  hydrosulphite  of  soda  is  made 
thus : — Place  some  zinc  turnings  in  a  100  gramme 
flask,  and  fill  it  three  parts  full  with  water.  Add  10 
c.  c.  of  a  solution  of  bisulphite  of  soda,  of  a  specific 
gravity  of  1*16  (which  should  have  been  saturated  with 
sulphurous  acid  by  passing  a  current  of  this  gas  through 


NATURE  OF  THE  ORGANIC  MATTER         87 

it  for  several  hours).^  Insert  a  caoutchouc  stopper  and 
agitate  several  times.  In  half  an  hour  the  re-agent  is 
ready.  The  liydrosulphite  of  soda  differs  from  the  bi- 
sulphite only  by  an  atom  of  oxygen.  In  presence  of  free 
oxygen  it  instantly  absorbs  this  body  and  is  converted 
into  the  bisulphite 

SaOaNaOHO  -f-  O2  =  S^O^NaOHO 

There  are  colouring  matters,  such  as  "  Coupler's  soluble 
aniline  blue,"  which  are  instantaneously  decolourized  by 
the  liydrosulphite  of  soda,  though  they  resist  the  action 
of  the  bisulphite.  For  instance,  if  to  a  litre  of  water  well 
freed  from  air  by  boiling,  and  coloured  faintly  with 
Coupler's  blue,  we  add  dilute  liydrosulphite  of  soda,  avoiding 
access  of  air,  we  shall  observe  that  a  few  drops  are 
sufficient  to  destroy  the  colouration.  If,  on  the  contrary, 
the  water  is  aerated,  the  decolouration  is  not  produced  until 
enough  liydrosulphite  has  been  added  to  absorb  all  the. 
dissolved  oxygen.  If  the  solution  of  liydrosulphite  of 
soda  were  capable  of  being  preserved,  it  would  be  merely 
requisite  to  determine  once  for  all  the  volume  of  oxygen 
which  a  known  volume  of  the  liquid  can  absorb ;  but,  in 
consequence  of  its  great  instability  it  is  necessary  to 
standardize  the  solution  every  time  before  its  employment. 
This  is  easily  effected  by  the  decolouration  which  the 
liydrosulphite  of  soda  produces  in  a  solution  of  the 
ammoniacal  sulphate  of  copper,  as  it  reduces  cupric  oxide 
to  cuprous  oxide.  Bisulphites  and  sulphites  are  without 
action  on  the  solution  of  copper,  as  long  as  there  remains 
an  excess  of  ammonia.  We  prepare  then  a  strongly 
ammoniacal  solution  of  sulphate  of  copper  containing 
4-471  grammes  of  the  crystallized  salt  per  litre,  10   c.  c. 

^  Sulphurous  acid  gas  is  prepared  by  allowing  pure  sulphuric  acid  to 
act  on  clean  copper  cuttings,  and  must  be  washed  by  passing  it  through  a 
small  quantity  of  water.     Vide  any  book  on  chemistry. 


88  THE    DETERMINATION    OF    THE    AMOUNT    AND 

of  which  solution  having  the  same  action  upon  the  hydro - 
sulphite  of  soda  as  1  c.  c,  of  oxygen.  Suppose  that  we 
take  20  c.  c.  of  this  ammoniacal  copper  solution,  and  find 
that  17 '5  c.  c.  of  the  solution  of  the  hydrosulphite  of  soda 
are  needful  to  bring  the  blue  solution  to  a  colourless  state. 
We  know  that  the  20  c.  c.  correspond  to  2  c.  c.  of  oxygen. 
If  a  litre  of  the  water  to  be  examined,  slightly  tinted 
with  Coupier's  blue  requires  36-4  c.  c.  of  the  solution  of  the 
hydrosulphite  of  soda  to  be  decolourized,  we  have — 

x  =  36-4x2  ^  ,.,,,.        ^ 

=  4'16  c.  c.  of  oxygen  dissolved  per  litre  oi  water. 


17-5 

There  remains  a  small  correction  to  be  applied  for  the 
quantity  of  hydrosulphite  of  soda  needful  to  decolourize 
the  Coupier's  blue  employed,  which  may  be  determined 
once  for  all. 

This  process  is  marvellously  sensitive.  If  two 
portions  of  the  same  water  are  taken,  and  one  is 
poured  boldly  into  a  beaker  whilst  the  other  is  allowed 
to  flow  quietly  down  the  side  of  a  beaker,  the  two  will 
show  a  decided  difference.  The  testing  should  be  per- 
formed in  a  vessel  which  exposes  as  little  surface  to  the 
air  as  possible,  stirring  must  be  minimized,  and  a  little 
light  petroleum  oil  or  pure  mineral  naphtha  may  be  poured 
on  to  the  surface  to  exchide  oxygen. 

Dr.  Tidy  has  made  a  few  observations  on  Thames 
water ^  which  show  that  the  oxygen  in  solution  during 
the  winter  months  (November  to  April)  is  very  nearly 
double  the  amount  held  in  solution  during  the  summer 
months  (May  to  October),  being  2-19  in  the  former  case 
and  1'19  cub.  in.  per  gallon  in  the  latter,  the  least 
oxygen  being  thus  present  during  the  months  of  the 
greatest  organic  purity. 

^   "  River  "Water,"  Joiornal  of  Chemical  Society,  vol.  xxxvii.  18S0. 


NATUKE  OF  THE  ORGANIC  MATTER 


89 


Dr.  Dupr^  has  also  made  similar  observations^  on  the  Dr.  Dupre's 
Thames  water  at  various  points  from  Eichmond  towards tiojjg' 
the  sea. 

Permanganate  of  Potash  Test. 


Teddington  Weir 

<JX 

J'geu  ausurueu  j^jcr  gaii 

•109 

Chelsea 

•165 

Greenwich 

•204 

Barking 

•272 

Northfleet 

•151 

Thames  Haven   . 

•106 

Yantlet  Creek     . 

•070 

Dissolved  Oxygen  Test. 

Percentage  of  Aeration 

Richmond  Bridge              .               .              .100 

Kew  Bridge 

100 

Hammersmith  Bridge 

67-3 

Westminster  Bridge 

54-5 

'Tunnel 

25 

Barking  Creek    . 

19-7 

Jenningtree  Point 

23^3 

Erith      . 

23-7 

Northfleet 

38^1 

Coal  House  Point 

52-6 

Hole  Haven 

75 

Southend 

96 

Both  processes  show  the  gradual  increase  of  pollution 
in  the  water  of  the  river  as  the  sewage  outlet  of  the 
metropolis  at  Barking  Creek  is  approached,  and  its  gradual 
diminution  when  proceeding  from  this  point  to  the  sea. 
In  a  recent  experimental  research  "  On  Changes  in 
Aeration  of  Water  as  indicating  the  Nature  of  Impurities 
present  in  it,"^  Dr.  Dupre  has  shown  the  probability 
that  chemistry  may  enable  us  to  distinguish  between 
living  organic  matter  and  dead  organic  matter.  The 
samples  of  water  on  which  he  operated  were  fully  aerated 

^  Analyst,  July  and  September  1885. 

^  Fourteenth  Annual  Report  of  the  Local  Government  Board,  1884-85, 
containing  Supplement  of  Medical  Officer  for  1884. 


90         NATURE  OF  THE  ORGANIC  MATTER 

by  vigorous  shaking  and  maintained  at  the  same  tem- 
perature. He  found  that  a  peaty  water  {dead  organic 
matter)  took  more  oxygen  from  the  permanganate  of 
potash  than  from  the  oxygen  dissolved  in  the  water, 
and  that  a  water  containing  animal  organisms  consumed 
more  of  the  dissolved  oxygen  in  the  water  than  oxygen 
derived  from  the  permanganate  of  potash.  He  concludes 
thus  :  "  The  consumption  of  oxygen  from  the  dissolved  air 
of  a  natural  water  is  in  the  vast  majority  of  cases,  at  all 
events,  due  to  the  presence  of  growing  organisms,  and  in 
the  complete  absence  of  such  organisms  little  or  no 
oxygen  would  be  thus  consumed."  Our  powers  of  diag- 
nosis between  waters  containing  a  slight  excess  of  animal 
and  vegetable  organic  matter,  which  is  admittedly  difficult, 
are  likely  to  'be  increased  by  a  development  of  this 
scheme  for  estimating  the  dissolved  oxygen  in  a  water. 


CHAPTEE    III 

the  determination  of  the   mineral  products  result- 
ing from  changes  in  the  animal  organic  matter, 

1.  Ammonia, 

which'  is  in  itself  harmless,  is  a  product  of  the  clecom- Ammonia, 
position  of  anunal  organic  matter,  and  is  present  in  air 
in  exceedingly  variable  quantity,^  out  of  which  it  is 
washed  by  the  great  air-cleanser,  rain.  Eain  contains 
•49  part  per  million  of  ammonia.  Eiver  water  rarely 
possesses  more  than  "1  part  per  million  of  ammonia. 
Unpolluted  well  water  contains  less  than  this  amount, 
whilst  spring  water  is  generally  free  from  it. 

Excess  in  Rivulets  and  Shallow  Well  Waters. 

As  ammonia  in  contact  with  animal  matter,  and  Rivulets  and 
subject  to  oxidizing  influences,  is  very  rapidly  converted  ^^gyg°^ 
into  nitrates  and  nitrites,  its  presence  in  large  quantity 
in  rivulets  and  shallow  well  waters  indicates  their  very 
recent  and  direct  pollution  with  animal  matters.  The 
excess  is  always  accompanied  by  an  excess  of  albuminoid 
ammonia.  In  the  case  of  shallow  wells  a  contamina- 
tion of  the  water  by  urine  is  more  than  probable 
{vide  page  209). 

^  Vide  Ozone  and  Antozone,  p.  226. 


92 


DETEKMINATION    OF    MINEEAL    PRODUCTS    FROM 


Excess  in  Deep  Well  Water. 

Deep  wells.  Ammonia  is  found  in  considerable  quantity  in  the 
waters  of  some  deep  wells,  especially  of  those  that  enter 
the  sand-beds  which  lie  underneath  the  London  clay.  In 
these  waters  the  amount  of  albuminoid  ammonia  is  so 
exceedingly  small  as  to  preclude  the  possibility  of  sup- 
watersre-  posing  tlic  cxistcnce  of  any  animal  defilement.  Here, 
uownedfor  £q^  instancc,  are  the  analyses  of  three  waters,  all  from 

purit5'wnien  '  "^ 

contain  an   dccp  artcsiau  wcUs  situatcd  in  a  little  callage  : — 

excess  of  free 


A.  Depth  385  ft.    . 

B.  Very  deep 

C.  Depth  330  ft.    . 

MlLLIGEAililE   PER   LiTKE. 

Free  Ammonia. 

Alb.  Ammonia. 

•59 
•41 
•37 

•04 
•07 
■06 

Here  are  analyses  of  waters  of  another  village,  possess- 
ing locally  a  high  repute  for  purity : — 


A.  Depth  250  ft.    . 

B.  ,,       300  ft.    . 

MlLLIGRAililE   PEE   LiTPvE. 

Free  Ammonia. 

Alb.  Ainmonia. 

•76 
•74 

•04 
■03 

An  excess  of  free  ammonia,  when  associated  with  a 

permissible  amount  of  albuminoid  ammonia,  may  be  due 

either — 

Possible  1.   To  entrance  of  rain  water  into  well. 

presence  of         2.   To  tlic  bcneficial  transformation  of  harmful  organic 

an  excess  of  ]32atter  iuto  the  harmless  ammonia,  through  the  agency 

ammonia  in  t-%  i 

waters  free  01  sauQ,  clay,  and   other   substances,  which   act   on  the 
from  excess  -^^i^qj;.  {-^  g^  manner  similar  to  the  action  on  it  of  a  good 

of  organic  "-> 

matter.  filter. 


CHANGES    IN   ANIMAL    ORGANIC    MATTER  93 

3.  To  some  salt  of  ammonia  existing  in  the  strata 
through  which  the  water  rises  ;  or, 

4.  To  the  decomposition  of  nitrates  in  the  pipes  of  the 
well.  Mr.  H.  Slater  suggests  that  the  agent  concerned  in 
this  reduction  may,  in  the  case  of  the  deep  well  waters, 
be  the  sulphide  of  iron  which  is  found  in  the  clay. 

Ammonia  may  be  converted  into  nitrates  and  nitrites 
by  a  process  of  oxidation,  or  be  obtained  from  these 
salts  by  one  of  reduction.  We  conclude,  then,  that 
the  presence  of  free  ammonia  in  such  comparatively 
large  quantities  in  these  deep  well  waters  is  due  to  the 
reduction  of  nitrates  and  nitrites  by  sulphide  of  iron,  or 
some  kinds  of  organic  matter,  or  some  other  agent,  such 
oxidized  nitrogen  salts  having  been  produced  in  past 
ages  by  the  oxidation  of  organic  matter.  In  the  case 
of  deep  artesian  wells,  the  borings  of  which  pass  through 
the  London  clay  into  the  chalk  beneath,  the  nitrates 
that,  by  reduction,  furnish  the  waters  of  these  wells 
with  free  ammonia,  doubtless  come  from  the  chalk  itself. 
Sometimes  a  pure  deep  well  water  containing  a  minute 
quantity  of  free  ammonia  may  be  found  within  a  few 
yards  of  another  deep  well  water  equally  pure,  which 
exhibits  a  large  excess,  the  difference  between  the  two 
wells  being  only  one  of  depth  and  strata  perforated : — 


Water. 

Grs.  FEB  Gall. 

Paets  per  Million. 

Haedness. 

Solids. 

Chlorine. 

Free 
Amm. 

Alb. 
Amm. 

Well  175  feet  deep 
,,       50    „       ,, 

106-4 
98-0 

37-7 
36-6 

•01 
•63 

•0-2 
•01 

9^5 
4-5 

Mr.  AVanklyn  formerly  regarded  with  suspicion  a 
water  yielding  a  large  quantity  of  free  ammonia,  along 
with  •OS  part  per  million  of  albuminoid  ammonia. 
The    above    analyses    of    deep    weU    waters,   which   are 


9-i 


DETEEMIXATIOX    OF    MIXEEAL    PRODUCTS    FEOM 


renowned  for  purity  throughout  all  the  country  in 
which  they  form  centres,  prove  that  he  was  wrong. 
In  the  fourth  edition  of  his  Water  Analysis  he  shows 
that  he  has  discovered  his  mistake,  but  he  altogether 
omits  to  make  any  allusion  to  his  error,  or  to  the  indi- 
vidual who  not  only  privately  but  publicly  pointed  it  out 
to  him.^    He  thus  signalizes  his  conversion  on  page  131 : — 

"  Well  230  feet  clee^j  at  Blaclfriars. 


Date. 

Grains  per  Gallon. 

Milligramme  per  Litre. 

Solids. 

Chlorine. 

Free 
Ammonia. 

Alb. 
Ammonia. 

July  20,  1876. 

57- 

10-2 

•80 

■05 

This  water  exhibits  what  is  occasionally  found,  namely, 
a  large  quantity  of  free  ammonia  in  pure  deep  spring 
water  of  the  first  class." 

Mr.  Allen  of  Sheffield  has  fallen  into  a  similar  error. 
He  writes,^  "  It  is  not  unusual  to  find  a  very  large 
proportion  of  ammonia  in  the  water  of  very  deep  wells. 
In  the  great  majority  of  instances  it  is  associated  with 
an  excessive  proportion  of  chlorides — a  fact  which  points 
to  sewage  or  urine  as  the  original  source  of  the  con- 
tamination." Both  statements  are  correct,  but  the  con- 
clusion arrived  at  by  him  is  altogether  wrong. 

Mr.  Wanklyn  has  accordingly  altered  his  standard  of 
rules  by  changing  the  wording  of  one  of  his  sentences. 
In  the  previous  editions  we  read,  "  I  should  be  inclined 
to  regard  with  some  suspicion  a  water  yielding  a  con- 
siderable quantity  of  free  ammonia,  along  uith  '05  part  of 
albuminoid  ammonia  per  million."    In  the  fourth  edition  he 


1  Yide     Water    Analysis  for    the    Medical 
edition,  p.  18. 

2  Public  Health,  February  9,  1877. 


xcer    of  Health,    first 


CHANGES    m    ANIMAL    ORGANIC   MATTER  95 

writes,  "  I  sliould  be  inclined  to  regard  with  some 
suspicion  a  water  yielding  a  considerable  quantity  of  free 
ammonia,  along  with  more  than  "05  part  of  albuminoid 
ammonia  per  million," — a  very  material  difference. 

The  mode  of  estimating  the  quantity  of  free  ammonia 
in  a  water  is  described  on  page  40. 

2.    XlTROGEN    AS    NiTRATES    AND    ISTlTRITES. 

The  controversy  between  Dr.  Frankland  and  Mr.  mtrates 
Wanklyn  concerning  their  respective  modes  of  water  ^"'^^.^^ 
analysis  has  waged  very  much  around  the  question  as  to 
the  value  of  an  estimation  of  the  amount  of  these  salts 
in  a  water.  Whilst  the  former  appears  to  give  a  pre- 
ponderating weight  to  the  indications  afforded  by  the 
past  history  of  a  water,  and  seems  to  consider  that  the 
determination  of  the  mineral  products  of  the  animal 
pollution  of  a  water  affords  the  key  to  the  whole  situa- 
tion ;  the  latter  denounces,  in  the  strongest  terms,  all 
reliance  on  the  presence,  in  any  quantity,  or  absence,  of 
these  products  of  the  oxidation  of  tilth.  Mr  Wanklyn 
says,^  "  It  cannot  be  too  strongly  insisted  upon  that 
the  nitrates  afford  no  data  of  any  value  in  judging  of 
the  organic  quality  of  a  water ; "  and  again,  "  The  pro- 
gress of  investigation  has  completely  discredited  the 
nitrates  as  criteria  of  unwholesomeness."^  The  pupils 
of  these  analysts  follow  very  closely  in  the  paths  of 
their  respective  teachers.  Dr.  Hill  of  Birmingham,  in 
his  Eeport  for  1876,  which  contains  a  sheet  of  the 
analyses  of  waters  from  114  different  private  wells,  shows 
that  he  forms  an  opinion  of  each  water  solely  from  the 
amount  of  the  products  of  oxidation,  such  as  nitrates  and 
nitrites,  coupled  with  the  proportion  of  chlorides,  without 

^  Oj}.  cit.     Fourth  edition,  p.  84. 
-  Hart's  Manual  of  Public  Health,  p.  309. 


96         DETERMINATION    OF    MUSTERAL    PRODUCTS    FROM 

ever  attempting  to  estimate  the  quantity  of  organic 
nitroo'en,  and  oro;anic  carbon  contained  in  each.  Mr. 
Thomas,  public  analyst  of  Cardiff,  also  states  that  if  he 
found  nitrates  and  chlorides  in  excess,  and  knew  that  this 
excess  could  not  be  ascribed  to  the  peculiar  character  of 
the  strata  from  which  the  water  was  derived,  he  should 
not  determine  the  organic  carbon  and  nitrogen  unless 
required  to  do  so,  but  would  immediately  condemn  the 
water.  This  exclusive  reliance  on  the  evidence  vouch- 
safed by  the  chlorides  and  nitrates  is  to  be  found  in  Dr. 
Cameron's  Manual  of  Hygiene.  On  page  71  he  writes, 
"  In  a  soft  water,  remote  from  the  sea,  the  decided 
presence  of  chlorine  and  nitric  acid  should  be  considered 
as  clear  evidence  of  previous  sewage  pollution,  and  such 
water  should  be  regarded  as  dangerous  to  health."  G. 
W.  Wigner,  F.C.S.,  also  writes  thus,-"-  "  There  are  many 
cases  where  a  sample  of  water  must  be  condemned  on 
the  evidence  of  nitrates,  nitrites,  and  the  microscope  only." 
Whilst  one  leader  is  at  one  extreme,  the  other  is  at 
the  opposite.  Looking  at  the  matter  judicially,  apart 
from  all  preferences  for  either  of  these  rival  processes, 
and  governed  simply  by  the  results  of  a  large  practical 
experience  of  all  kinds  of  water,  I  should  say  that  the 
truth  lies  midway, — 

"  Media  in  res  tutissimiis  ibis." 

Dr.  Erankland,  although  falling  into  the  mistake, 
whilst  judging  a  water,  of  making  his  decision  almost 
entirely  rest  on  the  degree  of  previous  sewage  contami- 
nation, and  the  amount  of  nitrates  and  nitrites,  makes 
the  following  statements,^  with  which  we  must  all  agree. 

In  the  presence  of  oxygen  the  nitrogen  of  animal 
matters   is   transformed,   in   great   part,   into   nitric   and 

^  Sanitary  Itecord,  October  19,  1877. 
'  Rivers  Pollution  Commission. — Sixth  Report. 


CHANGES    IN   ANIMAL    ORGANIC    MATTER  97 

nitrous  acids  ;  and  these,  by  combining  with  the  basic 
substances  always  present  in  polluted  water,  are  in  their 
turn  converted  into  nitrates  and  nitrites. 

The  change  is  most  rapid  and  complete  when  polluted 
water  passes  through  aerated  soil. 

Whilst  the  oxidation  of  animal  matters  in  solution  in 
water  yields  abundance  of  nitrates  and  nitrites,  vegetable 
matters  furnish  under  like  circumstances  mere  traces,  or 
none,  of  these  compounds. 

The  late  Mr.  Stoddart,  Analyst  for  Bristol,  directed  Bristol 
attention  in  the  Analyst  of  March  1878,  page  212,  first, 37pp[y_ 
to  the  abundance  of  diatoms  in  the  Bristol  water  supply, 
secondly,  to  the  production  of  ammonia  by  their  de- 
composition, and  thirdly,  to  the  origin  of  nitrates  from 
the  ammonia  thus  formed.  Notwithstanding  the  large 
quantity  of  diatoms,  the  amount  of  these  products  of 
their  decay  is  insufficient  to  raise  the  insignificant  pro- 
portions of  the  ammonia  and  nitrogen  as  nitrates  when 
diluted  with  such  immense  volumes  of  water  as  are 
contained  in  the  reservoirs. 

Upland  waters,  which  have  been  in  contact  only 
with  mineral  matters,  or  with  the  vegetable  matter  of 
uncultivated  soil,  contain,  if  any,  mere  traces  of  these 
salts ;  but  as  soon  as  the  water  comes  into  contact  with 
cultivated  land,  or  is  polluted  by  the  drainage  from  farm- 
yards or  human  habitations,  nitrates  in  abundance  make 
their  appearance.  The  presence  of  nitrates  and  nitrites 
in  sufficient  quantity  is  therefore  trustworthy  evidence  of 
the  previous  pollution  of  the  water  with  animal  matters. 

Nitric  and  nitrous  acids  are  present  in  minute  quantity 
in  the  air,  out  of  which  the  rain  washes  them.  In  71 
samples  of  rain  water  collected  at  Eothamsted,  near  St. 
Albans,  the  proportion  of  nitrogen,  as  nitrates  and  nitrites, 
varied  from  nil  up  to  '03  grain  per  gallon.  The  largest 
amount,  which  occurred  only  once,  was  exceedingly  small. 

H 


98 


DETERMINATION    OF    MINERAL    PRODUCTS    FROM 


Waters  which,  it  is  well  known,  cannot  be  defiled  by 
manure  or  by  sewage,  never  contain  nitrates  in  a  pro- 
portion bringing  them  near  to  the  "point  of  contamination." 

The  average  amounts  of  oxidized  nitrogen  found  by 
the  Elvers  Pollution  Commissioners  ^  in  the  pure  waters 
of  the  various  geological  strata  are  as  follows : — 


Nitrogen  as  Nitrates  and  Nitrites. 


Eain 


Grain  per  Gallon. 
•002 


Upland  Surface  Water. 
(From  Non-calcareous  Strata.) 
From  Igneous  Eocks       ...... 

„      Metamorpliic,  Cambrian,  Silurian,  and  Devonian 
Rocks      ..... 

„     Millstone  Grits     .... 

(From  Calcareous  Strata.) 
.From  Mountain  Limestone 

„     Lias,  Trias,  and  Permian  Rock 

„     the  Oolites  .... 

Deep  Well  Water. 
In  the  Coal  Measures     .... 

New  Red  Sandstone 

the  Chalk 

,,        ,,     below  London  Clay 
Devonian  Rocks  and  Millstone  Grit 
the  Lias  ..... 

,,    Oolites        ..... 
,,    Hastings  Sand,  Greensands,  and  Weald  Clay 

Spring  Water. 
From  Granite  and  Gneiss  Rocks 

„     Devonian  Rocks  and  Old  Red  Sandstone 

,,     New  Red  Sandstone 

,,     the  Lias       .... 

,,       ,,  Hastings  Sand  and  Greensand 

„      Silurian  Rocks 

„     Mountain  Limestone 

„     Millstone  Grits  and  Coal  Measures 

,,     the  Oolites 

„       „    Chalk 

1  Ojy.  cit. 


•001 

•004 
•007 

•008 
•007 
•03 

•14 

•5 

•4 

•05 

•2 

•3 

•4 

•1 

•07 
•5 
•2 
•3 

•2 

•12 

•16 

•24 

•28 
•27 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  99 

The  Ohjcdions  of  Mr.  Wanklyn  and  those,  who  think 
with  him,  to  the  Determination  of  Nitrates  and 
Nitrites,  may  he  thus  summarized : 

1.  Nitrates  find  their  way  into  waters  from  the  various  oi^jections 

,.,  1-11  f>  Tin*°  ^^®  s^^ti- 

geological  strata  which  they  traverse ;  lor  example,  chalk  mation  of 
springs,  which  contain  an  infinitesimal  amount  of  organic  ^^!^|;^^*^®^^^'^*^ 
matter,  are  often  highly  charged  with  nitrates. 

2.  The  processes  of  vegetation  in  rivers  and  lakes  are 
calculated  to  withdraw  nitrates  from  the  water ;  accord- 
ingly, an  absence  of  nitrates  may  be  due  to  a  rife  aquatic 
growth  as  well  as  to  absence  of  sewage. 

3.  Eaw  sewage  is  said  to  be  free  from  nitrates. 

The  examples  adduced  in  support  of  these  statements 
prove  nothing.  If  we  examine  seriatim  the  objections 
themselves,  we  shall  find  that  they  amount  to  very  little. 

1.  Nitrates  are  found  in  excess  in  certain  pure  waters  Answers  to 
from  the  chalk,  but  the  largest  amounts  discovered  do  1!^^  °^'^®'^' 

'  o  tions. 

not  generally  exceed  "7  grain  per  gallon,  an  amount  which 
would  simply  throw  suspicion  on  the  water  of  a  shallow 
well,  or  of  a  spring,  if  this  result  was  confirmed  by  other 
evidence.  Knowing  this  peculiarity  in  the  waters  of  deep 
wells  in  the  chalk,  namely,  that  they  possess  an  excess, 
and  sometimes  a  large  excess,  of  nitrates,  the  objection 
falls  to  the  ground. 

2.  It  is  perfectly  true  that  vegetable  life  assimilates 
these  salts,  and  so  removes  them,  especially  in  spring  and 
summer.  Accordingly,  their  amount  will  then  show  a 
slightly  more  favourable  result  than  really  exists  during 
the  quiescent  months  of  the  year.  This  optimist  indica- 
tion in  the  growing  season  appears  to  be  a  very  feeble 
objection,  especially  when  it  is  remembered  that  the 
estimation  of  the  nitrates  and  nitrites  is  only  one  of 
several  data  on  which  an  opinion  of  a  water  should  be 
based. 


100      DETEEMINATIOX    OF    MINERAL   PEODUCTS    FROM 

3.  In  undiluted  sewage  putrefaction  rapidly  occurs, 
during  wliich  process  the  nitrates  are  destroyed.'^  I 
cannot  consider  this  as  a  valid  objection. 


Utility  of  the  Estimcdion  of  Oxidized  Nitrogen  Scdts. 

utility  of  the  The  presence  of  an  excess  of  these  salts  in  a  water 
tionof^°^  affords  no  indication,  taken  by  itself,  that  such  water 
Nitrates  and  (Reserves  Condemnation,  nor  does  the  complete  absence 
of  nitrates  and  nitrites  warrant  any  one  in  pronouncing 
a  water  to  be  pure.  Some  of  the  purest  waters,  such, 
for  example,  as  those  from  deep  wells  in  the  chalk, 
contain  much  nitrates,  which  have  aptly  been  termed 
fossil  organic  matter,  or  the  skeleton  of  sewage ;  whilst 
waters  so  full  of  vegetable  matter  as  to  be  injurious  to 
health  may  not  contain  a  vestige  of  them.  The  estima- 
tion of  the  amount  of  these  salts  not  only  teaches  us,  as 
to  whether  the  soil  from  which  the  water  is  derived  is 
clean  or  defiled  with  filth  which  it  has  oxidized,^  but, 
taken  in  conjunction  with  other  e^ddence,  it  affords  valu- 
able aid  to  us  in  the  formation  of  an  opinion.  Although 
the  water  of  a  well  far  away  from  any  chalk  may  be 
found  to  be  organically  pure,  yet  the  presence  of  any 
large  quantity  of  nitrates  and  nitrites,  which  are,  so  far 
as  our  knowledge  extends,  harmless  in  themselves,  informs 

1  Some  believe  tliat  in  sewage,  nitrogenous  organic  matter  is  destroyed 
•without  the  formation  of  niti'ates,  the  nitrogen  being  evolved  in  the  form 
of  gas ;  whilst  others  consider  that  when  sewage  is  allowed  to  stand,  a 
process  of  fermentation  occurs,  and  as  this  subsides,  oxidation  commences 
with  the  formation  of  nitrates  and  nitrites  at  the  expense  of  the  organic 
matter  and  the  ammonia. 

^  The  contrast  displayed  by  samples  recently  sent  to  the  author  of  the 
water  of  the  River  Jordan,  which  contains  a  mere  trace  of  nitrogen  as 
nitrates  and  nitrites,  and  that  of  the  Pool  of  Siloam,  which  holds  in 
solution  more  than  22  grains  of  nitric  acid  per  gallon,  whilst  each  water 
exhibited  between  30  and  40  grains  of  chlorine  per  gallon,  is  very  striking. 


CHANGES    IN    ANIMAL    OEGANIC    MATTER  101 

US  tliat  the  water  is  in  imminent  danger  of  pollution. 
This  discovery  tells  us  that  the  natural  oxidizing  process 
of  cleansing  and  purification  by  the  soil  is  proceeding. 
Experience  teaches  us  that  ■  a  tune  will  come,  and  we 
know  not  how  soon,  when  the  soil  will  become  overdone 
with  filth,  and  will,  at  first  imperfectly,  and  at  length 
finally  cease  to,  cleanse  by  filtration  the  polluted  water, 
when  the  organic  matters  will  themselves  enter  the  well ; 
or  the  organic  animal  filth  may  be  washed  into  the  well 
at  any  moment  by  a  sudden  downfall  of  rain.  The 
presence,  then,  of  these  salts,  in  considerable  proportion, 
in  shallow  well  waters,  in  non- chalky  districts,  is  an 
ominous  sign.  A  public  analyst  has  recently  written : — 
"  Nitrates  in  a  deep  well  water  represent  fossil  excreta, 
but  nitrates  in  a  shallow  well  water  represent  recent 
excreta."  The  former  part  of  the  sentence  is  true  enough, 
but  the  latter  is  misleading.  I  have  known  shallow  well 
waters  in  chalky  districts,  that  could  not  possibly  have 
been  defiled,  exhibit  an  excess  of  nitrates. 

There  exists  a  widely  spread  dread  lest  the  poisons  of 
diseases,  be  they  soluble  or  in  the  form  of  micro-organisms 
or  of  infinitesimal  insoluble  particles,  may  survive  the 
almost  complete  oxidation  by  earth  of  dead  organic 
matter,  and  may  co-exist  with  nitrates  and  nitrites  in  a 
water  devoid  of  any  excess  of  organic  matter.^      Some, 

^  This  fear  has  recently  been  very  forcibly  expressed  by  Dr.  Ashby  and 
Mr.  Hehner  ("On  So-called  Previous  Sewage  Contamination,"  in  Analyst, 
April  1883),  with  resxiect  to  waters  from  the  surface  wells,  7  or  8  to  20  or 
25  feet  in  depth  in  Derby  and  Newark-on-Trent.  These  waters  come  from 
the  variegated  marl  of  the  trias,  the  marlstone  rock-bed  of  the  middle 
lias,  and  the  chalk.  They  seem  as  a  class  to  be  notorious  for  high  solids, 
an  excess  of  nitric  acid,  phosphoric  acid,  sulphuric  acid,  and  chlorine 
associated  with  a  comjmratively  small  amount  of  free  ammonia  and 
albuminoid  ammonia.  Some  soils  soon  lose  the  power  of  oxidizing 
filth,  especially  if  overdone  with  it;  whilst  others  may  be  converted 
into  a  nitre  bed,  and  still  retain  the  property  of  carrying  on  this  purify- 
ing change. 


102      DETERMIlSrATION    OF    MINERAL    PRODUCTS    FROM 

indeed,  believe  that  water  from  a  well  within  a  yard  or 
two  of  a  cesspool  cannot  possibly  be  pure.  I  have 
known  several  wells  in  clay  soil,  varying  in  distance  from 
one  to  live  yards  from  cesspools,  which  have  supplied 
water  of  the  greatest  purity,  their  safety  being  due  to  the 
retentive  properties  of  the  clay,  and  the  water-tight  con- 
dition of  the  cesspools.  I  am  acquainted  with  a  family 
that  has  for  years,  without  apparent  ill  effects,  been 
drinking  water  from  a  well  in  porous  gravelly  soil,  within 
two  yards  from  an  enormous  cesspool,  which  is  evidently 
not  water-tight.  The  water  is  organically  pure,  but  con- 
tains between  1  to  2  grains  per  gallon  of  nitrogen  in  the 
form  of  nitrates  and  nitrites.  Highly  dangerous  of  course 
it  is  to  drink  such  water,  for  the  well  may  be  defiled,  or 
the  earth  may  cease  to  act  as  an  efficient  filter,  at  any 
instant.  The  curious  spread  of  typhoid  fever  at  Lausen, 
in  Switzerland,^  by  water  that  had  passed  through  an 
immense  thickness  of  earth,  has  excited  the  suspicion  that 
the  poison  of  enteric  fever  may  possibly  be  a  soluble 
Prof.  Mai-  rather  than  an  insoluble  particle.  Under  the  supervision 
let's  experi-    £   p    £    Mallet   a   numbcr   of   natural   waters    believed 

ments  m  tlie 

United       to  be  good  and  wholesome,  including  the  regular  water 

states  u  o 

supply  of  some  of  the  principal  cities  of  the  United 
States,  were  arranged  together  as  class  1  ;  and  a  number 
of  natural  waters,  which  there  was  fair  ground  for 
beliei-ing  had  actually  caused  disease  on  the  part  of  those 
drinking  them,  were  arranged  as  class  2.  Both  series  of 
waters  were  examined  by  the  Frankland  Combustion 
process,  by  the  Wanklyn,  Chapman,  and  Smith  process, 
and  the  Letheby  and  Tidy  permanganate  process,  with 
this  result — "No  marked  difference  exists  between  the 
highest,  loivcst,  or  average  result  obtained  by  any  of  the 
processes  for  the  waters  of  class  1  and  the  corresponding 

^  Beitriige  zur  Untstehimgsgcschichte  cles  Typhus  und  zur  Trinhwasser- 
lehre. — Yon  Dr.  A.  Hauler. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  103 

result  for  those  of  class  2.  No  one  could,  with  these 
figures  to  guide  them,  refer  a  water  of  unknown  origin  to 
one  or  other  of  the  two  classes  on  the  evidence  afforded 
by  chemical  analysis,  using  either  or  all  of  the  processes 
in  question."  On  examining  these  same  waters  for 
nitrates  and  nitrites  "  we  find  a  very  obvious  connection 
between  the  results  of  chemical  examination  and  the 
known  sanitary  character  of  the  several  waters,  the  salts 
of  nitrous  and  nitric  acid  being  either  absent  or  present 
in  but  trifling  amount  in  waters  of  class  1,  believed  to  be 
wholesome ;  whilst  they  were  almost  universally  present, 
and  in  many  cases  in  large  quantity,  in  the  pernicious 
waters  of  class  2." 

Griess  has  expressed  ^  a  strong  opinion  as  to  the 
unfitness  of  water  for  drinking  purposes  which  contains 
nitrates  and  nitrites.  Dr.  Angus  Smith  writes,^  "  the 
presence  (of  nitrates)  shows  that  the  most  dangerous 
state  of  the  organic  matter  is  past.  The  water  may, 
however,  be  still  dangerous  to  use."  Ekin  states  that^ 
"  waters  which  have  undoubtedly  given  rise  to  typhoid 
fever  have  been  found  by  the  writer  over  and  over 
again  not  to  contain  more  than  '05  part  of  albuminoid 
ammonia  in  1,000,000,  and  which,  notwithstanding  their 
containing  a  large  excess  of  nitrates,  have  been  passed 
by  analysts  of  undoubted  ability  as  being  fit  for  drink- 
ing purposes."  E.  Haines  of  Philadelphia  has  pub- 
lished *  cases  which  partially  corroborate  the  opinions  of 
Mr.  Ekin. 

Here  is  an  analysis  of  a  well  water  kindly  sent  to  me  Examples, 
by  Dr.  Armistead,  of  the  Cambridgeshire  district,  which 
would   have   been  j)assed   as   pure  if  sole   reliance  had 

^  Ann.  d.  Chem.  u  Pharni.  cliv.  336. 

2  C'/iemic(«?  iVcics,  September  3,  1869.  ^  "  Potable  Water." 

^  "  Methods  of  judging  of  the  wholesomeness  of  Drinking  Water,"  from 
Journal  of  the  Frankland  Institute,  February  1881. 


104      DETERMINATION    OF    MINEKAL    PKODUCTS    FROM 

been  placed  on  the  indications  afforded  by  the  Wanklyn, 
Chapman,  and  Smith  process : — 


Grains  per  Gallon. 

Milligramme  per  Litre. 

Clilorine. 
4- 

Free  Ammonia. 
•14 

Album.  Ammonia. 
•06 

The  amount  of  clilorine  did  not  exceed  the  average  for 
the  neighbourhood.  Suspicions  were  aroused  when  the 
well  was  found  to  be  near  a  churchyard,  and  oxides  of 
nitrogen  were  sought  for.  These  filth  products  were 
found  in  abundance,  and  a  considerable  quantity  of 
phosphates  were  also  discovered. 

Here  is  another  example  of  a  water  that  would  have 
been  deemed,  if  trust  had  solely  been  placed  on  the 
amount  of  free  and  albuminoid  ammonia,  to  be  of  indif- 
ferent quahty,  but  passable  : — 


Free  ammonia 
Albuminoid  ammonia 


Milligrainme  per  Litre  = 
Part  per  Millon. 

•005 

•10 


Chlorine  in  excess,  but  not  above  the  average  of  the  pure 
waters  in  the  vicinity.  Nitrogen,  as  nitrates  and  nitrites, 
3*7  grains  per  gallon.  This  water  came  from  a  well 
which  proved,  on  inquiry,  to  be  situated  in  a  highly 
dangerous  place.  Such  a  water,  exhibitmg  so  large  a 
proportion  of  nitrates  and  nitrites,  deserved  condemna- 
tion. 

Here  is  a  third  analysis,  of  the  water  from  a  well  25 
feet  deep,  w^hich,  as  regards  its  organic  contents,  would 
be  pronounced  of  the  utmost  purity  : — 


Grains  per  Gallon. 

Milligramme  per  Litre. 

Solids. 
23- 

Chlorine. 
2-2 

Free  Ammonia. 
•01 

Alb.  Ammonia. 
•04 

As  there  was  an  excessive  brilliancy  about  the  water, 


CHANGES   IN    ANIMAL    OEGANIC    Mx\.TTER  105 

my  suspicions  were  aroused ;  so  I  examined  the  water 
for  nitrogen  in  the  form  of  nitrates  and  nitrites,  of 
which  I  found  I'll  grains  per  gallon.  My  opinion,  ex- 
pressed to  the  applicant,  was  that  the  water  was  pure  at 
the  time  of  analysis,  but  was  in  great  danger  of  pollution ; 
that  the  soil  cleansed  the  water  at  present,  but  would 
cease  to  do  so  after  a  certain  period,  when  filth  would 
enter  the  well.  The  applicant  then  informed  me  that 
there  was  a  cesspool  two  or  three  yards  from  the  well. 
How  would  the  Wanklyn,  Chapman,  and  Smith  process, 
unaided  by  the  estimation  of  the  nitrates,  have  enabled 
me  to  see  the  danger  ahead,  and  sound  the  note  of 
warning  ? 

The  analyses  made  by  the  late  G.  W.  Wigner  of  the 
water  supply  of  Clactou  on  Sea,^  where  the  proportion  of 
free  ammonia  and  albuminoid  ammonia  was  very  low, 
whilst  the  amount  of  nitrates  was  high,  and  the  micro- 
scope disclosed  the  presence  of  numerous  particles  of 
decomposed  muscular  fibre,  etc.,  are  of  interest  in  con- 
nection with  the  subject  under  consideration.  Many 
additional  instances  could  be  given,  if  space  permitted,  to 
show  the  value  of  an  estunation  of  the  nitrates,  but  such 
must  surely  be  unnecessary. 

The  omission  to  pay  any  regard  to  the  amount  of 
nitrates  and  nitrites  in  a  water  is  practically  to  ignore 
the  infiltration  of  filth  into  a  water  supply  that  is  not 
very  recent. 

It  is  not  needful  in  every  case  to  make  a  cpiantitative 
examination  of  the  nitrogen  as  nitrates  and  nitrites.  If 
any  doubt  exists  after  estimating  the  amount  of  free 
ammonia,  albuminoid  ammonia,  and  chlorine — if  one's 
diagnosis  is  somewhat  obscured  by  any  curious  results — 
if,  indeed,  there  is  the  slightest  haze  or  mist  in  connection 
with  an  analysis,  it  is  wise  to  calculate  the  quantity  of 

^  Sanitary  Record,  August  31,  1877. 


106      DETERMINATION    OF   MINERAL   PRODUCTS    FROM 

nitrates  and  nitrites.  I  should  not  think  of  making  an 
estimate  of  these  salts  in  the  water  of  a  spring,  far 
removed  from  any  filth,  that  is  always  running,  or  in  an 
artesian  well  water,  respecting  both  of  which  there  existed 
no  suspicion,  and  both  of  which  showed  infinitesimal 
amounts  of  free  and  albuminoid  ammonia.  In  Dr. 
Armistead's  analysis  the  numbers  of  these  two  kinds  of 
ammonia  afforded  a  suspicious  indication;  and  in  the 
analysis  which  immediately  follows  it,  the  quantity  of 
albuminoid  ammonia,  coupled  with  the  knowledge  of  the 
dangerous  position  of  the  well,  would  have  led  me  to  test 
for  salts  of  nitrogen. 

Qualitative.  A.    QUALITATIVE    EXAMINATION. 

The  Horsiey       The  HoTsUy  Test. — The  directions  given  by  the  dis- 
"^*^^*'  coverer  of  this  test  are  as  follows  : — Take  a  large  sized 

conical  test  glass  holding  about  1-|-  or  2  oz.  of  the  water 
to  be  examined,  and  dissolve  in  it,  by  the  aid  of  a  glass 
rod,  about  1  grain  of  pyrogallic  acid.  Measure  out  1-|^  or 
2  fluid  drachms  of  pure,  strong  sulphuric  acid.  The  test 
glass  containing  the  water  and  pyrogallic  acid  being  held 
in  the  right  hand  and  its  edge  depressed,  carefully  pour 
down  the  side  of  the  vessel  the  sulphuric  acid,  which 
will  lie  as  a  layer  underneath  the  water.  Drop  gradually 
into  the  water  a  pinch  of  salt.  When  the  salt  reaches 
the  sulphuric  acid,  effervescence  takes  place  which 
mingles  the  upper  and  lower  layers,  giving  rise  in  the 
lower  layer  to  a  more  or  less  purplish  violet  or  black 
colour,  according  to  the  quantity  of  nitrates.  Nitrites,  if 
present,  will  show  themselves  in  the  upper  layer  by  pro- 
ducing a  yellowish  or  even  brown  tint  indicative  of  nitrous 
acid  in  a  gaseous  state,  which  gradually  disappears  {vide 
fig.  11).  Twice  distilled  water  remains  colourless  when 
treated  as  above. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  107 


Nttrites 


Nitrates 


Dr.  Bond  of  Gloucester  practises  the  following  modi- 
fication, which  is  preferable: — 20  minims  of  pure 
sulphuric  acid  are  placed  in  a  very  small  test  tube, 
to  which  1 0  minims  of  the  water  to  be  examined 
are  added.  One  drop  of  a  solution  of  pyrogallic  acid 
(10  grains  to  1  ounce  of  distilled  water  acidulated 
with  2  drops  of  sulphuric  acid)  is  then  dropped  into 
the  mixture.  The  depth  of  the  dark  amethyst  or 
vinous  brown  coloration  is  a  measure  of  the  amount 
of  the  salts  present. 

It  is  wise  to  make  one  or  two  blank  experiments 
with  twice  distilled  water,  when  fresh  chemicals  are 
employed,  so  as  to  be  assured  of  their  purity.  After 
allowing  the  colour  to  develop  for  a  few  minutes,  the 
contents  of  the  test  glass  should  be  shaken,  so  as  to 
mix  the  sulphuric  acid  with  the  water,  and  no  opinion 
should  be  formed  as  to  the  water  under  examination 
until  a  quarter  of  an  hour  has  elapsed  after  such  com- 


108      DETERMINATION    OF    MIXEEAL    PRODUCTS    FEOM 

mingling  has  been  effected.  It  will  be  found  useful 
to  keep  some  spring  water,  or  other  waters  containing 
known  quantities  of  nitrates  or  nitrites,  ready  at  hand, 
with  which  to  make  comparisons.^ 

It  is  stated  that  if  nitrates  are  alone  present,  the  tints 
will  be  of  an  amethyst  and  dark  brown  hue,  whilst  the 
exclusive  existence  in  a  water  of  nitrites  is  shown  by  a 
preponderance  of  a  reddish  brown  or  vinous  red  colour. 
This  Horsley  test  is  found  to  convey  very  useful  informa- 
tion to  those  who  make  a  study  of  it,  and  is  especially 
convenient  in  travelling,  as  it  does  not  involve  the 
conveyance  of  any  cumbrous  apparatus,  A  portable  and 
safe  arrangement  may  be  made  by  fitting  up  a  small  box 
with  the  following  articles  : — Pure  strong  sulphuric  acid 
in  a  capped  stoppered  tube  bottle  enclosed  in  a  vulcanite 
tube  case ;  solution  of  pyrogallic  acid  in  a  capped  dropping 
bottle ;  stoppered  test  glasses,  each  marked  by  a  file  to 
indicate  the  height  reached  by  20  minims  of  sulphuric 
acid  :  and  a  minim  measure. 


Nitric  Acid  or  Nitrous  Acid  ? 

The  occurrence  of  nitrites  in  springs  and  deep  well 
waters,  otherwise  unobjectionable,  is  without  significance ; 
for  their  presence  indicates  the  result  of  a  reduction  by 
some  mineral  substances  or  ancient  organic  matter  of 
nitrates  into  nitrites   and  ammonia.      The  determination 

1  The  Medical  Officer  of  Health  may  find  it  convenieiit  to  prepare  a  few 
standard  waters,  made  by  mixing  J  gr. ,  ^  gr. ,  1  gr. ,  2  grs. ,  3  grs. ,  and  4  grs. 
of  nitrate  of  potash,  each  with  a  gallon  of  distilled  water. 

Mr.  Horsley  makes  standards  by  dissolving  1  grain  of  nitrate  of 
ammonia  in  100  drops  of  distilled  water  and  adding  the  solution  in 
different  quantities  to  16  ounces  of  distilled  water  thus  : — 

5  drops  to  16  ounces  of  distilled  water  =  ^  gr.  per  gallon. 
10     „  „  „  =lgr. 

20     „  ,,  ,,  =2  grs. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  109 

of  nitrites  in  river  waters  is  of  little  value,  for  tliey  often 
derive  these  salts  from  the  manure  applied  to  the  arable 
land  which  they  drain. 

It  is  sometimes  desirable,  in  the  case  of  shallow  well 
waters  that  are  threatened  with  pollution,  to  ascertain 
whether  the  oxidized  nitrof^en  is  in  the  form  of  the  higher 
oxide,  viz.  nitric  acid,  or  the  lower  oxide,  viz.  nitrous 
acid.  If  all  the  combined  nitrogen  is  in  the  form  of 
nitrates,  which  contain  an  atom  more  of  oxygen  than 
nitrites,  we  know  that  a  complete  oxidation  of  the  organic 
matter  has  occurred.  If  the  nitrates  are  accompanied  by 
nitrites,  we  learn  that  this  oxidation  is  imperfect,  and  not 
thorough.  Lastly,  if  the  nitrites  abound,  we  conclude 
that  contamination  is  near  at  hand,  that  the  soil  is  over- 
done with  filth,  and  that  it  is  only  able  very  imperfectly 
to  cleanse  the  water.  These  are  the  broad  lessons  learnt 
by  making  a  discrimination  between  these  two  oxides  of 
nitroo-en. 

Nitric  Acid.  Kitric  Acid. 

Brucine  Test. — Evaporate  2  c.  c.  of  the  water  to  be 
examined  in  a  small  Berlin  dish,  about  the  size  of  a 
watch  glass,  to  dryness  over  a  spirit  lamp.  Add  one 
drop  of  strong  pure  sulphuric  acid  to  the  saline  residue. 
Endeavour,  as  far  as  possible,  to  bring  the  drop  in  con- 
tact with  all  the  saline  residue  by  tilting  up  the  dish. 
Allow  the  smallest  crystal  of  brucine  to  fall  on  the  drop. 
If  nitric  acid  be  present  in  even  the  minutest  quantity 
the  drop  of  sulphuric  acid  will  become  pink,  and  after- 
wards of  a  yellow  colour.  The  late  Prof.  Parkes  says,"^ 
"  Half  a  grain  of  nitric  acid  per  gallon  gives  a  marked 
pink  and  yellow  zone."  "•01  grain  per  gallon  can  be 
easily  detected." 

Prof.   Sanders,  who   represents    to   some    extent    the 

^  Manual  of  Practical  Hygiene.     Fifth  Edition. 


110      DETERMINATION    OF    MINERAL    PRODUCTS    FROM 

opinions  of  his  German  fellow-countrymen,  considers^ 
that  a  water  to  be  deemed  pure  should  contain  no 
appreciable  amount  of  nitric  acid. 

Nitrous  Acid. 

Potassium  Iodide  and  Starch  Test. — Boil  a  little 
powdered  starch  in  distilled  water  so  as  to  form  a  thin 
solution.  Place  a  little  of  the  water  to  be  examined 
in  a  test  tube,  and  add  about  5  minims  of  a  solution  of 
potassium  iodide,  free  from  iodate  (5  grains  to  1  ounce  of 
distilled  water),  and  a  little  of  the  cold  starch  solution. 
Pour  into  the  mixture  a  few  drops  of  pure  sulphuric  acid. 
If  the  water  contains  nitrous  acid  or  nitrites,  a  blue 
colour  will  be  produced,  in  depth  of  tint  proportioned  to 
the  amount  present. 

Permanganate  of  Potash,  as  described  on  pages  34 
and  35. 

Meta-phcnylene  Diamine  is  a  more  delicate  test,  since 
it  is  capable  of  detecting  one  part  of  nitrogen  in  ten 
million  volumes  of  water.  A  solution  of  sulphuric  acid 
should  be  prepared  by  mixing  one  volume  of  strong 
sulphuric  acid  with  two  volumes  of  distilled  water. 
Half  a  gramme  of  meta-phenylene  diamine  should  be 
dissolved  in  100  c.  c.  of  distilled  water,  decolourized  if 
necessary  by  passing  it  through  animal  charcoal,  and 
rendered  acid  with  sulphuric  acid.  1  c.  c.  of  each  of 
these  solutions  is  added  to  about  100  c.  c.  of  the  water 
to  be  examined  in  a  Nessler  glass.  If  nitrous  acid  be 
present  a  yellow  colour  is  produced,  the  depth  of  tint 
being  proportioned  to  the  amount  present.  The  chief 
objection  to  this  test  is  that  the  development  of  colour  is 
slow,  the  final  shade  not  being  reached  for  twenty 
minutes. 

1  Sandbiich  der  offentUchen  Gesundheitspflege.     Leipsig :  Hirzel.     1877. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  111 

A  still  more  delicate  test  for  nitrous  acid  exists, 
which  enables  one  part  of  this  acid  to  be  detected  in 
1,000^000,000  parts  of  water,  and  which  has  been 
employed  in  air  analysis  {vide  page  357). 

B.    QUANTITATIVE    EXAMINATION.  Quantitative. 

Experience  has  shown  me  that  it  is  of  no  practical 
service  whatsoever  for  sanitary  purposes — in  fact  a  waste 
of  time — to  estimate  to  the  third  decimal  point  the  amount 
of  nitrates  and  nitrites ;  for  such  extremely  accurate 
results  should  not  influence  our  opinion  respecting  a 
water  in  one  way  or  the  other.  Dr.  Erankland  and  his 
followers  exaggerate  the  importance  of  the  determina- 
tion of  minute  amounts  of  these  salts.  The  majority 
of  them  subtract  from  the  figures  which  they  obtain 
•0224  grain  per  gallon,  as  an  allowance  for  the  amount 
of  inorganic  nitrogen  in  rain  water.  The  average 
total  amount  of  ammonia,  nitrates,  and  nitrites  in  a 
pure  upland  surface  water  is  "0077  grain  per  gallon,  or 
practically  nil.  Dr.  Erankland  would  then  make  a 
deduction  of  "0224  grain  per  gallon  on  account  of 
the  ammonia  in  rain ;  or,  in  reality,  more  than  the 
total  quantity  of  inorganic  nitrogen  contained  in  this 
pure  water. 

There  is,  as  we  all  know,  a  strong  tendency  in  nature 
to  the  establishment  and  maintenance  of  an  equilibrium. 
Eoughly  and  generally,  it  may  be  said,  that  the  excess  of 
inorganic  nitrogen  that  may  find  its  way  into  the  soil,  and 
into  streams  and  lakes,  through  the  washing-out  of  the 
ammonia  in  the  air  by  rain,  is  compensated  for  by  the 
abstraction  of  the  ammonia  by  vegetation  on  land,  and 
the  removal  of  the  nitrates  and  nitrites  by  aquatic  plant 
life. 

The  quantitative  processes  for  the  estimation  of  the 


112      DETERMINATION    OF    MINEEAL    PRODUCTS    FROM 

nitrogen  products  of  the  oxidation  of  organic  matter  are 
very  numerous.  The  aluminium  process  of  Schultze 
(modified  by  Chapman  and  Wanklyn)  and  Walter  Crum's 
process  with  mercury  (as  modified  by  Frankland  and 
others),  and  the  indigo  process,  have  been  perhaps  the 
most  popular.  The  objection  to  the  first  is,  that  it  is 
useless  for  waters  containing  large  quantities  of  nitrates ; 
and  the  objection  to  the  second  is,  that  it  necessitates  the 
employment  of  large  and  costly  apparatus  for  the  measure- 
ment of  gases,  and  an  expensive  mercurial  bath.  The 
third  process  is  still  employed,  although  grave  doubts  have 
been  thrown  on  its  accuracy. 

A  number  of  sanitary  analyses  were  some  years  ago 
published,-^  in  which  the  estimation  of  the  nitrates  would 
seem  to  have  been  made  by  means  of  the  indigo  process. 
The  experience  of  myself  and  some  others  with  it  has  been 
most  unsatisfactory,  on  account  of  the  difficulty  in  obtaining 
concordant  results.  As  some,  however,  entertain  a  belief 
in  its  value,  it  is  perhaps  desirable  to  refer  to  it  somewhat 
in  detail.  Fischer,^  Boussingault,  Marx,  Trommsdorff, 
Goppelsrceder,  and  Bemmelen,  have  worked  particularly 
at  this  indigo  process  in  various  ways,  but  the  most  recent 
mode  of  applpng  it  is  that  described  by  Sutton.^  An 
investigation  has  also  been  made  at  the  Eothamsied 
Laboratory  as  to  the  value  of  the  indigo  process,^  which 
appears  to  have  been  of  an  exhaustive  character,  A  few 
extracts  from  the  papers  referred  to  may  advantageously 
be  given,      "  The  method  of  running  indigo  from  a  burette 

^  "On  the  "Water  Supply  of  Seaside  Watering-Places,"  by  tlie  late 
G.  W.  Wigner,  F.C.S.,  in  Sanitary  Record,  commencing  in  jSTo.  165, 
August  24,  1877,  and  appearing  in  subsequent  numbers. 

-  Journ.  Pract.  Chemie.  (2)  vii.  57. 

^   Volumetric  Amdysis. 

^  "On  the  Quantitative  Determination  of  T^'itric  Acid  by  Indigo,"  by 
Robt.  Warington,  in  Chemical  News,  February  2  and  9,  1877,  and  in 
Journal  of  Chemical  Society,  1879,  vol.  xxxv.  p.  578. 


CHANGES    IN    ANIMAL    OEGANIC    MATTER  113 

into  a  nitrate  solution  mixed  witli  a  fixed  quantity  of 
sulphuric  acid  can  never  yield  reliable  results."  "  The 
tints  obtained  differ  somewhat  according  to  the  proportion 
of  sulphuric  acid  used,  the  mode  in  which  it  is  added, 
and  other  circumstances :  the  presence  of  chlorides  also 
affects  the  colour."  After  pointing  out  that  nearly  all  the 
purest  distilled  oil  of  vitriol  that  is  sold  contains  either 
nitrous  acid  or  sulphurous  acid  and  other  reducing  im- 
purities, and  sometimes  both  of  these  acids,  and  that  it  is 
necessary  for  the  operator  to  himself  purify  his  oil  of 
vitriol,  the  author  writes  : — "  The  various  writers  on  the 
subject,  from  Marx  to  Sutton,  all  recommend  the  use  of  a 
double  volume  of  oil  of  vitriol.  We  have  seen  that  with 
this  large  proportion  of  sulphuric  acid  the  errors  caused, 
both  by  organic  impurities  and  by  impurities  in  the  acid 
itself,  are  at  their  maximum.  Evidence  has  also  been 
adduced  to  show  that  with  this  proportion  of  acid  the 
indigo  scale  has  not  the  same  value  in  every  part. 
Chlorides  tend  to  reduce  the  amount  of  indigo  required." 

Notwithstanding  these  warnings  of  its  fallacious 
indications  published  in  1878,  it  was  employed  in  the 
Governmental  inquiry  conducted  in  1880-81  by  Dr. 
Cory,  to  the  results  of  which  is  appended  the  following 
sentence : — "  The  presence  of  albumen  in  the  water  in- 
terferes with  the  indigo  test  and  prevents  it  from  indicating 
the  true  amount  of  nitric  acid  present." 

The  proceedings  of  the  Society  of  Public  Analysts  of 
February  16,  1881,  informs  us  that  Dr.  Dupre  spoke  very 
strongly  of  "  the  failure  of  the  indigo  method  in  certain 
waters  "  and  of  the  probability  that  it  broke  down  in  nearly 
every  case.  "  It  broke  down  entirely  in  the  presence  of 
urine  in  water  and  almost  entirely  with  albumen  in  water." 

A  study  of  the  researches  at  Eothamsted  cannot  fail 
to  render  any  one  a  convert  to  the  conclusion  of  Mr. 
Warington  and  his  fellow- workers  respecting  the  indigo 

I 


V.  Har- 

court  and 


114      DETEEMINATION    OF    MINERAL    PEODUCTS    FEOM 

process  as  it  has  been  and  is  applied,  namely,  that 
"it  can  only  be  exact  under  very  exceptional  circum- 
stances." 

Vernon  Harcourt's  process  for  the  estimation  of  nitrogen 
siewerfs  in  uitratcs,  which  has  been  modified  by  Siewert,-*^  of  zinc- 
process.  ^^^^  couplcs  and  caustic  potash,  is  not  adapted  for  sanitary 
work.  The  determination  of  nitric  acid  by  means  of 
its  reaction  with  ferrous  salts,^  and  by  means  of  the 
platinum  magnesium  couple,^  are  two  of  the  most  recent 
methods.  The  copper-zinc  couple  process,  and  the 
sulphophenic  acid  process  of  MM.  Grandval  and  Lajoux, 
to  be  presently  described,  are  to  be  recommended  in 
preference  to  all  others. 

Modification  of  Thorji's  Process  for  the  Estimation  of  the 
Nitrogen  as  Nitrates  and  Nitrites. 

Modification  Thorp's  proccss  for  the  estimation  of  these  salts  is 
process.^  ^  bascd  ou  the  fact  discovered  by  Dr.  Gladstone  and  Mr. 
Tribe,  that  a  thin  plate  of  zinc,  coated  with  copper,  de- 
composes water,  and  that  the  hydrogen  evolved  is  capable 
of  reducing  nitric  acid  in  combination  into  nitrous  acid 
and  then  into  ammonia. 

NO3K  +  4H2  =  NH3  +  HKO  +  2H2O 

The  apparatus,  as  depicted  in  the  accompanying 
engraving  (fig.  12)  is  first  cleaned  with  tap  and  afterwards 
with  distilled  water. 

Five  grammes  of  the  thinnest  zinc  foil,  which  has 
been  thoroughly  cleansed  from  all  grease,  cut  with  a 
scissors  into  little  squares  about  the  size  of  a  5 -centi- 
gramme weight,  are  then  placed  on  a  piece  of  paper  ready 

^  Sutton's  Volumetric  Analysis. 

-  R.  "Warington  (1882).      Trans.  Chem.  Socy.,  xli.  345. 

3  F.  P.  Perkins  (1881).     Analyst,  April,  p.  58. 


CHANGES    IN    ANIMAL    OEGANIC    MATTER 


115 


for  use.  Some  strong^  solution  of  sulphate  of  copper 
(made  by  dissolving  the  pure  salt  in  distilled  water)  is 
introduced  into  a  flask  of  the  capacity  of  ^  litre,  or  1 
deci-gallon,  provided  vfith  a  long  neck  and  thick  strong 
mouth  for  the  insertion  of  an  india-rubber  cork.  The 
quantity  of  the  solution  should  be  sufficient  to  cover  the 
fragments  of  zinc  foil  when  they  are  introduced.  The 
solution  should  be  gently  warmed  over  a  Bunsen's  burner, 


Pig.  12. 
a.  Flask. 
6.  Condenser — medium  size. 

c.  Receiver,  whicli  resembles  a  very  large  Nessler  glass,  provided  with  an  india- 

rubber  cork. 

d.  U  Tube  containing  25  c.  c.  of  distilled  water. 

e.  Bunsen  burner  with  chimney. 

and  the  bits  of  zinc  foil  should  then  be  passed  into  the 
flask.  The  zinc  should  not  be  allowed  to  float  on  the 
solution.  A  gentle  swaying  motion  will  suffice  to  cause 
them  to  sink.  Let  the  copper  solution  act  on  the  zinc 
for  about  ten  minutes,  when  the  scraps  of  zinc  will  have 
become  perfectly  black  by  the  copper  deposited  on  them. 
A  copious  firmly  adherent  coating  of  black  copper  is 
desirable.     If  the  zinc  has  not  entirely  lost  its  metallic 

^  The  Society  of  Public  Analysts  recommends  the  employment  of  a 
three  per  cent  solution. 


116      DETEEMINATION    OF    MINEEAL    PRODUCTS    EKOM 

appearance,  the  solution  of  sulphate  of  copper  has  not 
acted  on  it  sufficiently  long.  Spongy  flocculent  masses 
of  copper,  easily  detached  from  the  zinc  by  washing,  will 
be  noticed  if  the  exposure  of  the  zinc  to  the  solution  of 
copper  has  been  too  long.  When  the  zinc  is  well  coated 
with  copper,  pour  off  the  copper  solution  as  completely  as 
possible.  Fill  up  the  flask  with  tap  water  three  or  four 
times,  stopping  for  a  moment  on  each  occasion  in  order  to 
allow  floating  particles  to  subside,  and  pouring  the  water 
away  carefully  so  as  not  to  lose  any  of  the  couple.  Then 
half  fill  the  flask  with  distilled  water,  and  having  poured 
that  away  also,  add  about  300  or  325  c.  c.  of  distilled 
water.  The  flask  will  then  be  about  three-parts  full. 
It  is  not  wise  to  shake  the  contents  of  the  flask  about 
more  than  is  needful  to  wash  them  thoroughly,  for  violence 
tends  to  detach  the  spongy  coating  of  copper  from  the 
zinc.  Whilst  these  preparations  are  being  made,  70  c.  c. 
of  the  water  to  be  examined  should  be  undergoing 
evaporation  to  dryness  on  a  water  bath  in  a  Berlin 
porcelain  dish  of  the  diameter  of  4  inches.  25  c.  c.  of 
distilled  water  is  to  be  added  to  the  solid  residue,  together 
with  a  bit  of  recently  burnt  quickhme  (preserved  in  a 
stoppered  bottle)  about  the  size  of  a  hempseed,  and  the 
liquid  is  then  boiled  (to  decompose  any  urea  which  may 
present)  until  about  4  or  5  c.  c.  remain.  Care  should  be 
taken  in  boiling  that  none  of  the  fluid  be  ejected  from 
the  dish.  Pour  these  4  or  5  c.  c.  into  the  flask,  and 
thoroughly  wash  out  the  dish  in  which  the  water  was 
evaporated  with  as  little  distilled  water  as  possible,  trans- 
ferring the  washings,  which  generally  amount  to  15  or 
■20  c.  c,  to  the  flask.  If  the  presence  of  a  large  excess 
of  nitrogen  salts  is  probable,  a  U  tube  should  be  attached 
to  the  receiver,  into  which  25  c.  c.  of  distilled  water  have 
been  placed.  Distil  over  100  c.  c,  of  which  a  half  (50 
c.  c.)  should  be  placed  in  a  ISTessler  glass  and  2   c.  c.  of 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  117 

Nessler  test  be  added.  If  the  tint  is  deeper  than  can 
conveniently  be  measured,  as  for  example  that  of  "30  or 
•40  milligramme  of  ammonia,  take  5  or  10  c.  c.  of  the 
remaining  50  c.  c,  and  having  mixed  them  with  45  or 
40  c.  c.  (so  as  to  make  50  c.  c.)  of  distilled  water  in  a 
Nessler  glass,  add  2  c.  c.  of  Nessler  test.  The  depth  of 
tint  should  be  imitated  by  making  up  standards  with  the 
standard  ammonia  solution  (1  c.  c.  =  -01  milligramme  of 
ammonia),  as  in  the  Wanklyn,  Chapman,  and  Smith 
process.  If  the  tint  afforded  by  the  50  c.  c.  is  not  deeper 
than  can  be  conveniently  estimated,  the  amount  of 
ammonia  producing  it  is  simply  to  be  multiplied  by  2  to 
yield  the  quantity  for  100  c.  c.  If  5  c.  c.  or  10  c.  c, 
however,  be  taken,  the  result  should  of  course  be  multiplied 
by  20  or  10,  as  the  case  may  be,  in  order  to  obtain  the 
quantity  contained  in  the  100  c.  c. 

Whilst  this  calculation  is  proceeding  a  second  100 
c.  c.  is  distilling  over,  which  should  be  treated  like  the 
first.  During  the  examination  of  the  second  100  c.  c. 
a  third  distillate  is  passing  into  the  receiver.  Unless 
there  is  a  large  amount  of  nitrogen  salts  present  the 
third  distillate  need  only  be  50  c.  c,  and  this  quantity 
will  be  found  to  be  the  last  that  it  is  necessary  to  remove 
in  the  majority  of  cases,  as  all  the  ammonia  will  have 
distilled  over.  If  the  U  tube  has  been  employed,  the 
25  c.  c.  of  distilled  water  in  it  should  be  mixed  with 
an  equal  bulk  of  distilled  water  in  a  Nessler  glass  and 
tested  for  ammonia  with  Nessler  re -agent.  If  any 
colour  is  produced,  which  will  be  the  case  if  the 
nitrates  and  nitrites  be  very  abundant,  the  proportion 
should  be  measured  by  preparing  a  standard. 

Before  this  process  is  employed  for  the  determination 
of  the  nitrogen  as  nitrates  and  nitrites,  it  is  necessary  to 
ascertain  the  amount  of  impurities  in  the  chemicals  used. 
Ammonia,  like  soda,  is  omnipresent.     It  is  exceedingly 


118      DETERMINATION    OF    MINERAL    PRODUCTS   FROM 

difficult  to  get  anything  perfectly  free  from  either.  Ac- 
cordingly, three  or  four  blank  experiments  should  be 
made,  and  an  average  of  the  amount  of  free  ammonia 
yielded  by  the  chemicals  must  be  subtracted  from  the 
results  arrived  at  by  each  analysis  of  a  water.  The 
above-mentioned  quantities  of  my  chemicals  furnish  about 
•06  of  a  milligramme,  which  I  deduct  from  each  water 
analysis,  for  example — 

70  cub.  cents,  of  the  water  analysed  supplied. 

(1)  Distillate  of  100  c.  c.         .  -85 

(2)  Distillate  of  100  c.  c.         .  '02 

(3)  Distillate  of    50  c.  c.          .  '01 


Average  of  error 

■06 

•82 

Milligrammes. 

ATiiinonia. 

Ammonia. 

Nitrogen. 

171 

'82 
14 

328 
82 

Nitrogen. 

17)ll-48(    -67 
102 

141 

128 

119 

9 

Ans.  •GT  milligramme  of  nitrogen  in  70  c.  c.  of  water 
under  examination,  which  is  equivalent  to  '67  grain  per 
gallon.  As  70  c.  c.  is  what  has  been  termed  "a  miniature 
gallon,"  the  amount  in  milligrammes  of  nitrogen  from 
nitrates  and  nitrites  thus  found  represents  the  quantity 
of  this  element  in  grains  per  gallon. 

An  expeditious  modification  of  this  process  has  been 

1  The  atomic  or  combining  weights  of  ammonia  and  nitrogen. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  119 

suggested  ^  by  M.  W.  Williams,  and  recommended  by  m.  w. 
the  Society  of  Public  Analysts,  which  cannot,  unfor- ^^^^^"^^^^3 
tunately,  be  employed  in  the  case  of  waters  exhibiting  mode  of  em- 
any  tint  in  a  ISTessler  glass,  nor  with  those  containing^  °^™^"  ' 
magnesia  or  other  substances  capable  of  being  pre- 
cipitated by  the  Nessler  re-agent.  After  washing  the 
zinc  and  copper  couple  with  distilled  water,  which  should 
be  displaced  by  washing  with  some  of  the  sample  of 
water,^  the  wide-mouthed  stoppered  bottle  containing  the 
couple  is  filled  up  with  about  3  or  4  oz.  of  the  water 
under  examination.  The  stopper  is  then  inserted,  and 
the  contents  of  the  bottle  are  allowed  to  digest  in  a 
warm  place  for  a  few  hours,  ^  or  over  night.  If  the 
water  is  soft,  a  little  salt  quite  free  from  ammonia 
(1  part  to  1000)  should  be  added  to  hasten  the  reaction. 
As  the  nitrous  acid  formed  by  the  reduction  of  the 
nitrates  does  not  disappear  until  the  reaction  is  finished, 
a  small  portion  of  the  fluid  contents  of  the  bottle,  acidified 
with  sulphuric  acid,  should  be  tested  with  a  solution  of 
meta-phenylene  diamine,  which  gives  a  yellow  colour  in 
a  few  minutes  if  nitrous  acid  is  present  (vide  page  110). 
When  no  nitrous  acid  is  found,  the  water  is  poured  off 
the  couple  into  a  stoppered  bottle,  and,  if  turbid,  allowed 
to  settle.  From  2  to  10  c.  c.  of  the  clear  fluid  are 
withdrawn  in  a  graduated  pipette  and  placed  in  Nessler 
glasses,  where  they  are  made  up  to  50  c.  c.  with  distilled 
water,  and  titrated  with  Nessler  re-agent  in  the  ordinary 
way. 

1  Analyst,  Marcli  1881. 

^  Dr.  R.  B.  Lee  always  at  this  stage  adds  -5  gramme  of  oxalic  acid 
(free  from  ammonia  and  nitric  acid),  in.  order  to  precipitate  the  lime  and 
to  form  an  insoluble  compound  with  the  zinc. 

^  If  the  bottle  be  maintained  in  a  water  bath  at  a  temperature  of  from 
55°  F.  to  60°  F.,  the  reduction  will  be  rapid,  and  will  be  found  to  be  com- 
pleted in  from  1^  to  2  hours  ;  the  employment  of  oxalic  acid  permitting 
the  elevation  of  the  temperature  without  loss  of  ammonia. 


120      DETERMINATION    OF    MINERAL    PRODUCTS    FROM 

A  deduction  must  of  course  be  made  for  the  ammonia 
pre-existing  in  tlie  water  under  examination. 

MM.   Grandval  and  Lajoux's  Process  for  the 
Determination  of  Nitric  Acicl.'^ 

Grandval  Tliis  proccss  is  bascd  on  the  change  of  carbolic  acid  into 

Proc^sf'^^'^  P^^-"^^^  acid  under  the  influence  of  nitric  acid,  and  on  the 

intensity  of  colour  exhibited  by  the  picrate  of  ammonia. 
A  solution  of  sulphophenic  acid,  and  a  titrated  solution 

of  nitrate   of   potash   are  necessary.     The  sulphophenic 

re-agent  is  prepared  by  mixing 

Grammes. 

Carbolic  acid,  pure     ...  3 

Acid  sulphuric  .  .  .  37 

40 

The  titrated  solution  of  nitrate  of  potash  is  made  by 
dissolving  '9  3  6  gramme  of  this  salt  in  1  litre  of  dis- 
tilled water.  1  c.  c.  of  this  solution  contains  "0005 
gramme  of  nitric  acid  or  "0001  gramme  of  nitrogen. 

Method. — 10  c.  c.  of  the  water  to  be  examined  are 
evaporated  to  dryness  in  a  porcelain  dish  over  a  water 
bath.  The  dish  is  allowed  to  cool,  and  an  excess  of 
sulphophenic  acid  is  added.  This  re-agent  should  be  led 
by  the  help  of  a  glass  rod  around  the  sides  of  the  dish, 
so  that  no  particle  of  the  residue  may  escape  its  in- 
fluence. A  few  cubic  cents,  of  distilled  water  are  poured 
into  the  dish,  followed  by  an  excess  of  ammonia.  We 
should  continue  to  add  ammonia  until  the  yellow  colour 
produced  does  not  disappear  on  stirring  with  the  glass 
rod.  This  solution  of  picrate  of  ammonia  is  diluted  with 
distilled  water  so  as  to  bring  it  to  a  volume  suitable  for 
the  colorimeter  employed. 

"VVe  operate  in  the  same  way  on  a  certain  quantity  of 

^  C'ovij^tes  Rcndus,  July  6,  1885. 


CHANGES    IN    ANIMAL    ORGANIC    MATTER  121 

the  titrated  solution  of  nitrate  of  potash,  taking  care  to 
bring  the  sokition  of  the  picrate  of  ammonia  obtained  to 
the  same  volume  as  that  of  the  water  under  examination. 
In  the  analysis  of  a  drinking  water,  which  a  qualitative 
test,  such  as  Horsley's  P}Togallic  acid  test  (vide  page 
106),  has  shown  to  be  exceedingly  pure,  it  is  wise  to 
employ  only  1  c.  c.  of  the  titrated  solution  of  the  nitrate 
of  potash.  If  the  public  water  supply  from  one  of  our 
cities  or  towns  is  to  be  submitted  to  examination,  in 
which  a  qualitative  test  points  in  the  direction  of  purity, 
it  is  advisable  not  to  employ  more  than  2  or  3  or 
4  c.  c.  of  the  titrated  solution  which  we  evaporate  to  dry- 
ness, in  either  case  bringing  the  volume  operated  on  up 
to  10  c.  c.  by  the  addition  of  distilled  water.  It  is  some- 
times convenient,  in  order  to  be  able  to  judge  within 
certain  limits  of  the  amount  of  the  titrated  solution  of 
nitrate  of  potash  which  should  be  operated  upon,  so  as  to 
arrive  at  a  colour  similar  to  that  of  the  water  under  in- 
vestigation, to  keep  in  store  standard  solutions  of  nitrate 
of  potash  of  difierent  strengths  and  depths  of  colour.  I 
am  in  the  habit  of  using  as  a  colorimeter  a  pair  of 
Hehner's  tapped  graduated  Nessler  glasses,  and  in  cases 
where  there  is  no  need  for  great  acccuracy  they  answer 
well.  The  details  of  this  process  may  advantageously 
be  inserted.  Suspecting  a  water  under  treatment  in  my 
laboratory  whilst  writing  these  lines  to  be  an  impure  one, 
as  much  as  10  c.  c.  of  the  titrated  solution  of  nitrate  of 
potash  were  evaporated  to  dryness.  10  c.  c.  of  the  water 
to  be  examined  were  also  evaporated  to  dryness.  The 
residue  of  each  was  treated  as  above  directed.  The  solu- 
tion of  picrate  of  ammonia  in  each  dish  was  then  diluted 
up  to  the  5  0  c.  c.  mark  in  the  colorimeter.  The  5  0  c.  c. 
of  titrated  solution  exhibiting  the  darker  colour,  as  much 
as  30  c.  c,  were  run  off  by  the  tap,  and  the  remaining  20 
c.  c.  exactly  equalled  in  depth  of  tint  that  of  the  5  0  c.  c. 


122      DETERMINATION    OF    MIXEEAL    PRODUCTS    FROM 

of  tlie  water  under  examination.  It  will  be  remembered 
that  10  CO.  of  titrated  solution  of  nitrate  of  potash  ('001 
gramme  of  nitrogen)  were  contained  in  the  50  c.  c.  of 
titrated  solution  in  the  tapped  Nessler  glass. 

e.c.  of  titrated       ^a4tt  tofo^^l^  ^^f         ^^r^e  Gnunme 

^°^-  water  under  examination.  "^  ^^-  °^  '■^• 

50  :  20  ::     -QOl        =        '0004 

The  50  c.  c.  of  the  water  under  analysis  equal,  therefore, 
20  c.  c.  ("0004  gramme  of  nitrogen)  of  the  50  c.  c.  of 
the  titrated  solution  of  nitrate  of  potash.  As  only  10 
c.  c.  of  the  water  under  examination  were  operated  on, 
this  "0004  gramme  of  nitrogen  must  be  multiplied  by 
1 0  0  to  ascertain  the  amount  of  nitrogen  in  a  litre — 

•0004 
X  100 


■0400       gramme  per  litre  of  nitrogen. 
X  70 


2 "80 00    grains  per  gallon  of  nitrogen  as  nitric  acid. 

I  learn  that  this  method,  which  is  more  rapid  than  that 
of  the  copper  zinc  couple,  is  highly  approved  of  by 
American  analysts. 

There  are  two  objections  to  it :  (1)  that  it  entails  the 
employment  of  ammonia,  which  should  be  rarely,  if  ever, 
used  in  a  laboratory  where  processes  for  its  detection  and 
estimation  in  water  and  air  are  in  frequent  operation ;  and 
(2)  that  the  addition  of  sulphophenic  acid  to  the  residue 
of  a  water  which  contains  a  considerable  amount  of  nitric 
acid  is  attended  by  the  evolution  of  peroxide  of  nitrogen 
or  nitrous  acid,  which  is  thus  lost. 

Rules  for  Cruiclance. 
Spring  waters  contain  on   an   average   "2    grain   per 


CHANGES    IN   ANIMAL    ORGANIC    MATTEE 


123 


gallon  of  nitrogen  as  nitrates  and  nitrites.  The  water 
supplied  to  London  by  the  Thames  "Water  Companies 
possesses  about  "15  grain  per  gallon,  whilst  that  which 
is  furnished  to  the  metropolis  by  the  Kent  Company  from 
the  chalk,  holds  in  solution  about  '3  grain  per  gallon. 
Some  wells  that  enter  the  chalk  yield  a  larger  amount, 
viz. : — "6  and  •?  grain  per  gallon,  and  sometimes  much 
more  of  nitrogen  as  nitrates  and  nitrites,  in  other  words, 
of  fossil  organic  matter,  and  are,  notwithstanding,  per- 
fectly pure.  When,  however,  from  "3  to  '7  grain  per 
gallon  is  reached  in  waters  that  do  not  come  from  the 
chalk,  the  excess  becomes  an  increasingly  suspicious 
circumstance.  A  water  exhibiting  1'5  grain  per  gallon 
is  regarded  as  approaching  that  class  of  waters  which 
would  be  considered  dangerous  for  drinking  purposes. 
Peaty  waters  and  sewage  contain  none,  or  only  a 
minute  quantity. 

Examples. 


Sample  of  Water. 

NiTEOGEN  AS 

Nitrates  and 
Nitrites. 

Grains  per  Gal. 

Well,  P.B.R 

Art.  Well,  O.P.S.      . 
Art.  Well,  J.T. 
Well,  R.H.S.AV. 
Spring,  G.H.G.B.     . 
Gray's  Water,  Brentwood. 

1-11 
■09 

8-47 

2-55 

•26 

•67 

CHAPTEE    lY 

THE  DETEEMINATION"  OF  THE  AMOUNT  OF  SOLID  EESIDUE, 
ITS  APPEAEAXCE  BEFORE,  DURIXG,  AXD  AFTER  IGXI- 
TIOX,  AXD  THE  LOSS  OF  VOLATILE  MATTERS  THEREBY 
OCCASIOXED. 

A.  The  Amount  of  Solid  Eesidue. 

B.  The    Appearance   of   the    Sohd    Eesidue    Before, 

During,  and  After  Ignition. 

C.  The  Amount  of  Volatile   IMatters   burnt   off   by 

Ignition. 

A.   TJu  Amount  of  Solid  Residue  or  Scdine  Matters. 

The  mineral  constituents  conduce  in  conjunction  with 
dissolved  air  and  carbonic  acid  gas  to  render  a  water 
palatable.  Eain  water  and  distilled  water,  which  are 
almost  destitute  of  the  same,  are  notoriously  flat  and 
insipid.  The  saline  matters  have  been  improperly  called 
by  some  "  soKd  impurities."  Dr.  Frankland,  who  was  the 
originator  of  this  unfortunate  expression,  defends  its  use  by 
stating  that  the  solid  matters  in  water  are  "  quite  useless." 
A  medical  man  would  not  make  such  an  assertion,  un- 
supported as  it  is  by  any  trustworthy  evidence  known  to 
the  profession.  He  adds,  "  A  very  large  proportion  of 
the  potable  water  supplied  to  towns  is  employed  for 
washing  and  manufacturing  purposes,  and  here  the 
presence  of  a  large  amount  of  solid  matter  giWng  hard- 
ness to  tlie  water  is  undoubtedly  injurious."^  This 
1  Rivers  Pollution  Commission. —  Sixth  Sej.ioii,  p.  5. 


LOSS  OF  VOLATILE  MATTEES  AFTEE  IGNITION 


12i 


sentence  must  not  lead  to  the  inference  that  waters 
characterised  by  an  excess  of  salts  are  always  hard. 
Strongly  saline  waters  are  often  very  soft,  as  for  example 
the  waters  of  many  artesian  wells.  Highly  saline  and 
hard  waters  are  admitted  on  all  hands  to  be  extremely 
undesirable  as  supplies  to  towns,  and  are  especially 
objected   to   for   washing   and   business    purposes.       The 


Fig.  13. 


A.  Platinum  Dish. 

B.  Beaker  containing  Water. 
c.  Tripod  Stand. 

D.  Bunsen's  Burner. 

E.  Coarse  Wire  Gauze,  on  which. 


a  pipe  triangle  rests  to  support 
the  beaker. 
F.  Thick  bit  of  paper  between  Dish 
and  edge  of  Beaker,  to  permit 
of  escape  of  steam. 


excess  of  salts  in  such  cases  may  perhaps  be  termed 
impurities,  but  it  is  ridiculous  to  speak  of  the  small 
quantities  of  saline  matters  in  the  purest  (organically) 
spring  waters  as  impurities  ! 

To  estimate  the  amount  of  solid  residue  at  212°  F. 
proceed  thus : — 

Weigh  an  empty  platinum  dish  of  100  c.  c.  capacity, 
place  it  over  a  water  bath,  and  pour  into  it  25  c.  c.  of 
the  water  to  be  examined.  Evaporate  to  dryness.  Wipe 
the  outside  of  the    dish  quite  dry.     Again  weigh  the  dish 


126         AMOUNT  OF  SOLID  EESIDUE,  ITS  APPEAEANCE, 

promptly    to     avoid    the     error    from    deliquescence    of 

salts. 

For  example  : — Dish  and  residue         .  26*240  grammes. 

Dish  .  .  .  26-232 


Weight  of  residue        .  '008 

As  25  c.  c.  are  a  quarter  of  100  c.  c,  multiply  the 
result  bj"  4,  and  then,  to  arrive  at  the  number  of  grains 
per  gallon,  multiply  by  700  thus : — 

■008 
4 


•032 

700 

22-400 

The  water  contains  22-4  grains  per  gallon. 

It  was  formerly  the  practice  to  evaporate  100  c.  c. 
or  70  c.  c.  of  the  water  to  dryness.  If  70  c.  c.  are 
selected,  the  result  exactly  represents  the  number  of 
grains  per  gallon.  Time  is  however  saved  in  the 
analyses  of  several  waters  by  employing  a  smaller 
quantity  of  water.  The  objection  has  been  raised  that 
the  experimental  error,  inseparable  from  all  analytical 
operations,  would  fall  rather  heavily  on  such  a  small 
quantity  as  25  c.  c.  I  have  found,  without  taking  any 
extra  care,  a  variation  of  1  grain  per  gallon  in  the  results 
obtained  by  taking  the  large  and  the  small  amount,  a 
difference  of  not  the  slightest  practical  importance.  It  is 
quite  immaterial,  from  a  sanitary  point  of  \dew,  whether 
our  drinking  water  contains  22-4  or  23-4  grains  of  saline 
matters  per  gallon. 

Physicians  well  know  that  a  water  in  which  a  mode- 
rate quantity  of  salts  is  dissolved  (medicinal  waters  ad- 
ministered with  a  specific  object,  and  for  a  limited  period 


AND  LOSS  OF  VOLATILE  MATTERS  AFTER  IGNITIOX     127 

only,  are  of  course  excluded  from  consideration)  is  better 
than  one  possessing  an  excess ;  for  the  constant  imbibi-  saiine 
tion  of  fluids  strongly  impregnated  with  saline  substances '"^^"g"^*^ 
tends  to  diminish  the  richness  of  the  blood,  and  to  render 
some  people  anaemic.  Although  the  waters  from  the 
artesian  wells  in  Essex  contain,  as  a  rule,  a  very  minute 
proportion  of  organic  matter,  yet  they  hold  in  solution  a 
large  quantity  of  salts,  derived  from  sand  beds  beneath, 
and  sometimes  alternating  with,  strata  of  the  London  clay. 
These  waters,  associated  as  they  are  with  so  large  a 
quantity  of  saline  matters,  cannot  be  considered  so  whole- 
some as  waters  from  artesian  wells  containing  a  moderate 
amount  of  salts,  equally  free  from  a  deleterious  amount  of 
organic  matter.  I  have  often  seen  the  ill  effects  of  the 
continued  employment  of  waters  rich  in  saline  matters. 
Some  well  waters  have  been  found  to  contain  an 
enormous  proportion  of  salts.  I  once  analyzed  a  water 
from  an  artesian  well  which  held  in  solution  341  grains 
of  solids  in  each  gallon ;  and  have  examined  waters  ex- 
hibiting the  large  amounts  of  485  grains,  and  even  795 
grains  per  gallon.  Sea  water  is  stated  to  have  2400  and 
2700  grains  per  gallon  of  solids. 

Spring  water  of  the  best  quality  usually  contains 
about  14,  17,  18,  or  19  grains  per  gallon  of  solid 
residue.  A  water  should  not  possess  more  than  30  or 
40  grains  per  gallon  of  solids ;  but  waters  holding  a 
larger  amount  dissolved  in  them  are  in  certain  cases 
permissible,  if  the  salts  are  quite  harmless.  It  is  gene- 
rally found,  according  to  my  experience,  that  when  a 
water  contains  much  more  than  110  or  120  grains  of 
saline  matters  per  gallon,  the  public  will  complain  of  it 
as  brackish  or  hard,  and  refrain  from  employing  it  con- 
tinuously, unless  obliged  so  to  do. 


128        AMOUNT  OF  SOLID  RESIDUE,  ITS  APPEAEANCE, 

B.   T]u  Appearance  of  the  Solid  Residue  Before, 
During,  and  After  Ignition. 

The  eflfect  of  Miicli  may  be  learnt  as  to  the  character  of  a  water 
gni  lou.  -j^^  observing  the  solid  residue  obtained  by  the  evapora- 
tion of  a  w^ater  on  a  water  bath  to  dryness  before,  during, 
and  after  its  incineration  at  a  dull  red  heat ;  and  very 
little  knowledge  is  to  be  acquired  by  the  estimation  ot 
the  loss  on  burning  the  same. 

After  the  calculation  of  the  amount  of  solids,  the 
appearance  of  the  residue  is  carefully  observed  and  noted. 
The  platinum  dish  is  then  placed  on  the  pipe  triangle, 
which  rests  on  the  tripod  stand.  The  smallest  sized 
Bunsen's  burner  should  be  lighted,  and  held  by  its  foot 
in  the  hand.  The  flame  should  be  allowed  to  play 
gently  to  and  fro  around  the  bottom  and  sides  of  the 
dish,  so  as  to  raise  all  its  contents  in  turn  to  a  didl  red 
heat.  Heat  may  be  conveniently  applied  in  a  manner 
equally  gradual  and  gentle  by  holding  the  platinum  dish 
with  a  pair  of  laboratory  tongs  or  pincers  over  the  flame. 

It  will  be  found  that — 

1.  In  cases  where  a  water  is  practically  free  from  any 
organic  matter,  and  the  solids  are  principally  lime  salts, 
there  will  be  no  discoloration  of  the  residue  during  igni- 
tion. The  residue  will  become  whiter,  until  at  length  it 
assumes  a  clean  pearly-white  appearance. 

2.  In  cases  where  the  organic  matter  is  small  in 
amount,  there  is  a  slight  brownish  discoloration,  which  is 
very  fleeting,  and  passes  like  a  smoky  cloud  away  as  the 
ignition  proceeds,  leaving  the  residue  of  a  dirty  white  or 
neutral  colour.  If  no  charring  is  observed,  and  the  loss 
on  ignition  is  very  small,  that  loss  is  due  to  the  volatiliza- 
tion and  decomposition  of  saline  matters  and  not  to 
organic  matter. 

3.  When  the  organic  matter  is  in  still  larger  amount 


AND  LOSS  OF  VOLATILE  MATTEES  AFTER  IGNITION     129 

(especially  if  it  be  vegetable)  the  residue  blackens  in 
patches  or  waves.  The  colour  is  more  persistent ;  and, 
to  dissijDate  it,  the  flame  of  the  Bunsen's  burner  has  to 
be  steadily  directed  beneath  the  blackened  places. 

4.  When  the  organic  matter  is  excessive,  the  whole 
of  the  residue  blackens  rapidly,  even  in  the  upright  sides 
of  the  dish,  evolving  a  smell  of  burnt  feathers  when  of 
animal  origin.  The  colour  is  extremely  persistent,  and 
in  some  cases  it  is  very  difficult,  if  not  impossible,  to 
dispel  it  by  the  application  of  a  dull  red  heat.  In  bad 
waters  (especially  when  urine  is  present)  the  organic 
matter  disappears  from  the  bottom  of  the  dish,  but  at  the 
sides  there  is  frequently  a  black  residue  which  it  is 
extremely  difficult  to  burn  off  even  by  prolonged  ignition. 

Dr.  Ashby  has  noticed  that,  if  nitrates  are  abundant 
in  a  water  polluted  with  much  organic  matter,  there  will 
be  very  little  blackening  and  perhaps  not  much  darkening 
of  the  ignited  residue. 

The  residues  of  very  bad  waters  will  sometimes  defla- 
grate. The  tiny  sparks  visible  are  due  to  the  presence  of 
nitrates  in  excess.  An  iodized  starch-paper,  erroneously 
called  an  "  ozone  test,"  is  held  over  the  dish  by  some 
during  the  ignition  to  detect  any  nitrous  acid  that  may 
be  given  off.  Eed  fumes  are  sometimes  evolved  when 
these  oxidized  compounds  of  nitrogen  are  large. 

The  employment  of  the  olfactory  nerves  may  also  aid 
us.  The  smell  of  burnt  hair  or  horn  produced  by  the 
destruction  of  the  organic  matter  is  often  observed.  The 
development  of  a  strong  empyreumatic  odour  is  suggestive 
of  a  bad  water. 

The  smell  of  sulphurous  acid  is  not  uncommon,  in- 
dicating the  presence  of  sulphur  compounds.  The  residue 
of  a  very  bad  water  will  sometimes  emit  an  offensive 
smell  on  incineration. 

The  observations  of  Dr.  Shea  of   Eeading  on  water 

K 


130 


TABLE  OF  ANALYSES,  WITIi  | 


Name  of 
Sample  of  Water. 

Grains  Per  Gaxlon. 

MiLLlGEAilME  PER 

Litre  = 
Part  per  Million. 

Degrees. 

Solids. 

Chlorine. 

Nitrogen 
as  Nitrates 

and 
Nitrites. 

Free 
Anjinonia. 

Albu- 
minoid 
Ammonia. 

Total 
Hardness. 

Public  Artesian  well  at  S. 

85 

•36 

•01 

Shallow  well  at  B.'s,  Gay 
Bowers 

52 

9-2 

•30 

•44 

Spring  water  from  clay 
soil  supplying  G.  H., 
Great  Baddow    . 

23 

2-6 

■26 

•00 

•03 

13  or  14 

Shallow  well  belonging  to 
cottages  near  "  King's 
Arms,"  B. 

101 

12-5 

Above 
1-0 

•24 

Peaty  spring  water 

5 

1-1 

None. 

•03 

•11 

2or2i 

Shallow  well  of  B.  P.     . 

23 

2-2 

1-11 

•01 

•04 

Artesian  well  of  Mr.  P.  T. 

210 

31 

8-47 

•10 

•35 

37 

Shallow  well  of  Mr.   A, 
E.  of  G.  W. 

103 

16 

Abund- 
ant. 

•69 

■28 

New  public  shallow  well 
at  G.  S.  F.— Soil hlne 
clay  and  black  sand    . 

89-6 

8-2 

Very 
little. 

•13 

•02 

32 

132        AMOUNT  OF  SOLID  RESIDUE,  ITS  APPEARANCE, 

residues  agree  closely  with  my  own.  The  late  Prof. 
Parkes  has  laid  down  the  following  rules  for  the  guid- 
ance of  the  analyst,  on  which  I  could  not  place  much 
reliance : — 

"  Three  grains  per  gallon  of  either  vegetable  or 
animal  organic  matter  cause  some  blackening ;  six  grains 
per  gallon,  a  good  deal;  and  ten  grains  per  gallon,  a 
great  amount. 

The  preceding  analyses  are  not  selected  for  the  pur- 
pose of  confirming  or  verifying  the  accuracy  of  the 
foregoing  attempt  at  rules  for  guidance,  but  are  taken 
indiscriminately  from  my  note-book.  Instead  of  being 
illustrative  and  typical,  they  would  seem  to  exhibit  some 
variations. 

C.  The  Amount  of  Volatile  matters  burnt  off  ly 
Ignition. 

Volatile  The  amount  of  organic  matter  was  formerly  calculated 

Matters 

by  burning  the  dried  solids  and  noting  the  loss — a  most 
fallacious  mode  of  estimation, — for  the  water  of  crystal- 
lization is  driven  off,  carbonates  are  decomposed,  nitrates 
and  nitrites  disappear,  and  even  chlorides  ^  if  the  residue 
is  strongly  ignited.  This  "  loss  on  ignition  "  has  accord- 
ingly been  spoken  of  as  "  substances  driven  off  by  heat." 

Speaking  generally,  impure  waters  may  be  said  to 
lose  much  by  incineration,  but  this  statement  cannot 
safely  be  regarded  as  an  established  rule,  because  the 
exceptions  to  it  are  so  numerous.  ]\ir.  Allen  has  ex- 
pressed the  opinion  that  in  a  good  water  the  loss  on 
ignition  is  rarely  more  than  one-fifth  of  the  total  sohds 
in  weight. 

Dr.  Shea,  who  has  had  some  experience  with  silica 
residues,   states   that   such    residues    retain    water    very 

■^  An  intense  yellow  colour  imparted-  to  the  flame  of  the  Bunsen's 
burner  indicates  the  volatilization  of  chloride  of  sodium. 


AND  LOSS  OF  VOLATILE  MATTERS  AFTER  IGNITION     133 


persistently,  and  only  lose  it  on  strong  ignition ;  and 
that  an  impure  water  of  this  class  which  he  encountered 
lost  55  grains  out  of  129  grains  of  solids  per  gallon. 

I  have  known  good  chalk  waters  lose  12  and  14 
grains  per  gallon  on  ignition  of  the  solid  residue. 

If  the  Medical  Ofiicer  of  Health  should  decide  to 
ascertain  the  amount  of  "  substances  driven  off  by  heat," 
he  should,  when  he  takes  the  solid  residue,  evaporate 
70  c.  c.  instead  of  2  5  c.  c.  of  the  water  to  dryness,  unless 


Fig.  14.— a  Copper  Water  Bath. 

A,  Hole  for  Berlin  evaporating  dish.    B,  Hole  for  platinum  dish.    C,  Tripod  stand. 

D,  Aperture  of  safety  tube. 

N.B. — The  insertion  of  a  small  piece  of  paper  between  one  of  the  dishes  and  the  edge 

of  the  aperture  on  which  it  rests,  suffices  to  permit  of  the  escape  of  steam. 

he   possesses    a   first-rate   balance,   otherwise   small    dif- 
ferences cannot  be  measured. 

If  the  health  officer  thinks  it  requisite  to  estimate 
quantitatively  the  amount  of  nitrogen  as  nitrates  and 
nitrites,  the  proportion  of  solid  residue,  the  quantity  of 
volatile  substances,  and  to  note  the  appearances  of  the 
residue  before,  during,  and  after  the  application  of  a  dull 
red  heat,  it  will  be  found  most  convenient  to  employ  a 
water  bath,  similar  to  that  used  for  evaporating  milk  to 
dryness,  but  provided  with  larger  holes,  one  to  hold  the 


134 


AMOUNT    OF    SOLID    RESIDUE 


Berlin  evaporating  dish,  and  the  smaller  to  support  the 
platinum  dish. 

Dr.  F.  de  Chaumont  makes  the  following  entry  in  his 
hygienic  classification  of  waters  : — ^ 


1.  Pure  and  Whole- 
some. 

Under  1  grain  per 
gallon. 

Solids  on  incin- 
eration should 
scarcely  blacken. 


2.   Usahle. 
Under  3  grains  per 

gallon. 
Solids  may  blacken 
a  little,   but  no 
fumes  should  be 
given  off. 


3.  Suspicious. 
3  to  5  grains  per 

gallon. 
Much     blackening 

on    incineration, 

or  nitrous  fumes 

given  off. 


4.  Impure. 
Above  5  grains  per 

gallon. 

Much    blackening 

and  nitrous  fumes 

given  off,  or  smell 

of  burnt  horn. 


Remarl:s. 
In  peat  waters  tho 
incinerated  solids 
may  blacken  con- 
siderably. 


The  ignited  residue  in  the  platinum  dish  should  at  the 
conclusion  of  the  determination  of  the  volatile  matters  be 
reserved  for  the  application  of  the  test  for  phosphoric 
acid. 

1  Parkes'  Hygiene,     Fiftli  Edition. 


CHAPTER   V 

THE    DETERMINATIOX    OF    THE    AMOUNT    OF    CHLOPJNE 

The  estimation  of  the  amount  of  chlorine  in  a  water  observation 
is  in  some  circumstances  worth  little  in  itself,  unless  we^^'^°f'^°™'^ 

I  _        _     of  chlorine 

know    the    amount    of   organic   matter   contained   in  itofiittie 
The    determination   of   the   amount   of   chlorine   in    the^^^^p^™^''" 
water  of  a  district,  where  an  excess  of  chlorine  does  not^^ycaieuia- 

.      ,.  .  ,  .  T      :^        tionofquan- 

occur  m  all  waters,  is  an  mdirect  guide  as   to  whether  tity  of  am- 
or not  the  water  is   contaminated  with  sewage,      xjrine™™'^.^"'^ 

°  organic 

and  sewage  possess   a  large  amount  of  chlorides.      The  matter. 
presence  of  5   or   10   grains  of  chlorine  per  gallon  in  a 
water    is   a    suspicious   circumstance   in   such    localities. 
Good  natural  waters  contain,  on  an  average,  from  '7   to 
1"2  grains  per  gallon. 

Waters  from  the  greensand  formation,  and  from  the 
London    clay,    have    generally    an     excess    of    chlorine, 
derived  from  the  chloride  of  sodium  and  other  salts  of 
chlorine  in  the  sand.     The  waters  of  Essex,  which  come  some  geoio- 
from  layers  of  sea-sand  and  clay  enclosing  marine  fossils,  ^^^^^JjJ'^** 
possess  as  a  rule  a  great  deal  of  chlorine.     One  artesian  waters  con- 

,.,-r  .,  ji'.i-  ,  taining  an 

water,  which  I  examined  recently  m  this  county,  con- excess  of 
tained  as  much  as  103'6  grains  per  gallon.  chiorme. 

In  the  neighbourhood  of  the  sea,  which  is  always  con- 
tributing its  spray  in  greater  or  less  quantity  to  the  land, 
and  wherever  there  are  natural  deposits  of  salt,  an  excess 
of  chlorides  is  apt  to  be  found. 

A  Medical  Officer  of  Health,  whose  work  is  situated  in 


136     DETERMINATION    OF    THE    AMOUNT    OF    CHLOKINE 

a  district  where  waters  exhibit  an  excess,  should  ascertain, 
by  making  a  number  of  examinations  for  chlorine,  the 
average  amount  of  it  in  waters  from  wells  of  different 
depths.  Some  years  ago  a  tube  well  was  sunk  at  Deal, 
where  most  of  the  wells  are  brackish.  At  25  feet  the 
water  was  too  salt  for  use,  but  at  45  feet  fresh  water  was 
obtained  free  from  brackishness,  whilst  at  1 1 7  feet  it  was 
as  salt  as  brine.  If  a  sample  of  water  holds  in  solution  an 
amount  of  chlorine  below  the  average  in  the  district,  the 
probability  is  that  there  is  no  sewage  contamination.  If, 
on  the  other  hand,  an  excess  of  chlorine  is  accompanied 
by  an  excess  of  albuminoid  ammonia  and  ammonia, 
pollution  with  sewage  is  almost  certain.  If  sulphates 
were  found  to  be  in  very  small  quantities,  the  excess  of 
chlorine  would  be  shown  to  be  not  due  to  a  pollution  by 
urine,  for  tliis  excretion  contains  a  large  amount  of 
sulphur  salts.  The  amount  of  chlorine  is  also  a  guide  as 
to  the  quantity  of  the  salts  of  sodium,  potassium,  and 
magnesium  in  a  water. 

It  should  always  be  remembered,  then,  that  in  all 
cases  the  estimation  of  the  amount  of  chlorine  and  of 
ammonia  must,  to  possess  any  value  as  a  guide  to  the 
pollution  or  otherwise  of  a  water,  be  taken  in  con- 
junction with  the  quantity  of  organic  matter,  and  in 
doubtful  cases,  with  the  amount  of  the  nitrates  and 
nitrites. 

To  estimate  the  proportion  of  chlorine  in  a  water,  we 
must  proceed  thus  : — Place  70  c.  c.  of  water  to  be  ex- 
amined in  an  evaporating  dish,  and  add  a  minute  morsel 
of  neutral  chromate  of  potash  (free  from  chlorine).  Then, 
by  means  of  a  pipette  gTaduated  to  ^th  of  a  c.  c,  and 
filled  with  5  c.  c.  of  the  solution  of  nitrate  of  silver  (vide 
recipe  on  page  218),  this  standard  should  be  allowed  to 
drop  into  it  until  the  red  colour  produced  ceases  to 
disappear.      Directly   the  red   tint   becomes   permanent, 


DETEEMINATIOX    OF   THE   AMOUNT    OF    CHLORINE     137 

note  the  amount  of  nitrate  of  silver  solution  necessary  to 
attain  this  point.  Eun  a  little  more  nitrate  of  silver  into 
the  water,  to  be  sure  that  the  water  is  not  acid,  for 
chromate  of  silver  is  soluble  in  acids. 

I  believe  the  existence  of  a  free  acid  (non-gaseous)  in 
a  water  to  be  rare,  for  only  on  one  occasion  have  I  found 
the  chlorine  test  interfered  with  in  this  way.  In  this 
solitary  instance  a  minute  quantity  of  potash  was  intro- 
duced to  neutralize  the  acid,  and  the  fresh  sample  of  70 
c.  c.  thus  treated  was  operated  on.  The  number  of  c.  c. 
of  the  nitrate  of  silver  solution  employed  will  represent 
the  number  of  grains  of  chlorine  per  gallon. 

A  very  interesting  case  has  been  recorded  ^  by  Dr.  F. 
de  Chaumont,  showing  the  value  of  the  chlorine  test  in 
cases  where  a  water  has  been  vitiated  by  sewage  gases. 
The  water  of  a  house  in  London  where  typhoid  fever  had  Pollution  by 

,  nil.  .     •  1  psewer  gas, 

appeared    was    found    to    contam    a    large    excess    oiandfoui 
"  albuminoid    ammonia,"    and    but    a    small    amount    of P^®°"® 

'  faacalemana- 

chlorine.  A  sample  from  the  reservoir  of  the  company  tions. 
that  supplied  this  house  was  analyzed,  and  found  to 
possess  an  almost  identical  quantity  of  chlorine,  but  an 
extremely  small  proportion  of  "albuminoid  ammonia." 
It  was  ascertained  that  the  water  used  in  the  house  was 
derived  from  a  cistern,  and  that  it  was  vitiated  by  the 
poisonous  gases  ascending  through  its  overflow  pipe  from 
the  sewer.  On  disconnecting  the  overflow  pipe  the 
amount  of  "  albuminoid  ammonia  "  gradually  diminished. 
Dr.  Eobert  King  describes  ^  an  outbreak  of  enteric  fever 
in  his  own  family,  where  the  following  change  took  place 
in  the  water  supply  of  liis  house,  in  consequence  of  the 
contamination  of  one  of  his  cisterns  by  sewer  gas  through 
its  overflow  pipe  which  was  in  direci  communication  with 
a  drain. 

^  Lectures  on  State  Mcdiciiie,  p.  77. 
"  Medical  Times  and  Gazette,  August  2,  1879. 


138    DETEKMINATIOX    OF    THE    AMOUi\^T    OF    CHLOFJNE 


Part  per  1 

[ILLIOS. 

Free 

Alb. 

Ammonia. 

Ammonia. 

Water  Supply  of  House     . 

•010 

•060 

„             of  Cistern   . 

•025 

•240 

A  very  clear  and  brilliant  water  was  recently  sent  to 
me  by  a  medical  man  in  attendance  on  an  isolated  case 
of  enteric  fever  in  a  rural  district  of  Xorth  Devon,  which, 
whilst  possessing  an  unpleasant  odour,  and  a  large  excess 
of  organic  matter,  contained  only  1|-  grain  of  chlorine  per 
gallon,  and  no  nitrogen  as  nitrates  and  nitrites.  A  micro- 
scopic examination  exhibited  an  abundance  of  bacteria 
and  micrococci.  The  water  had  come  from  a  well,  the 
overflow  pipe  of  which  passed  into  the  contents  of  a 
garden  closet  at  a  lower  level,  with  the  evident  object  of 
cleansing  the  same.  The  water  was  contaminated  by  the 
foul  gaseous  emanations  proceeding  from  the  decomposing 
faecal  matter.^ 

The  discovery  of  an  excess  of  organic  matter,  accom- 
panied by  a  small  amount  of  chlorine  and  nitrogen  as 
nitrates  and  nitrites,  coupled  with  the  presence  of  bacteria 
and  micrococci,  would  tend  to  the  conclusion,  if  vegetable 
contamination  is  out  of  the  question,  that  sewage  in  the 
solid  or  liquid  form  has  not  been  the  cause,  but  that  the 
source  of  impurity  is  probably  gaseous. 

^  Yide  Disease  Prevention,  p.  45.     J.  and  A.  Churcliill. 


CHAPTEE  YI 

THE    DETEEMINATION    OF    THE    HAEDXESS 

The  degree  of  hardness  is  a  matter  to  be  considered  in 
pronouncing  on  the  wholesomeness  of  a  water.  The 
average  total  hardness  of  good  waters  is  between  3  and  14 
degrees.  Some  deep  artesian  wells  made  in  the  London 
clay,  extending  to  the  sandbeds  lying  underneath,  and 
occasionally  to  the  chalk  below,  furnish  water  that  is 
excessively  soft,  from  the  presence  of  bicarbonate  of  soda 
that  replaces  the  bicarbonate  of  lime  derived  from  the 
chalk.  The  deepest  clay  strata  have  doubtless  a  softening 
effect  on  the  waters  of  these  deep  wells  by  virtue  of  the 
precipitating  action  of  the  alumina  of  the  clay  on  the 
salts  held  in  solution.  Pipeclay  mixed  with  sea  water 
is  well  known  by  marines  to  soften  it  and  increase  its 
cleansing  properties. 

An  error  has  been  made  by  some  in  judging  of  the 
hardness  of  a  water  solely  by  the  amount  of  solid  residue 
contained  in  it.  Mr  Wynter  Blyth  writes,-^  "  It  is 
obvious  that  the  soft  waters  have  a  small  solid  residue ; 
the  hard  a  large.  A  water  with  8  or  10  grains  of  solid 
residue  is  a  moderately  soft  water ;  the  lake  waters,  with 
from  2  to  3  grains  of  residue,  are  extremely  soft  ;  whilst 
those  with  50,  60,  70,  and  80  grains  of  saline  residue 
must  be  hard ;  so  that  any  other  test,  except  taking  the 

^  Did.  of  Hyrjienc  and  Public  Health. 


140 


DETERMINATION    OF    THE    HAEDNESS 


solid  residue,  is  really  superfluous."  It  is  j)erfectly  true 
that  a  hard  water  will  have  a  large  solid  residue,  but  it 
is  quite  an  error  to  state  that  a  water  possessing  a  large 
solid  residue  will  always  be  hard. 

Here  are  examples  of  organically  pure  and  soft  waters 
exhibiting  a  large  excess  of  solids  : — 


Wells 

Solids— Grains  per 
Gallon. 

Total  Hardness— Degrees. 
Clark's  Scale. 

A.  Steeple. 

B.  Do. 

C.  Maldon. 

D.  Tilliiigham. 

98 
103 

84 
236 

44 
5 
4 
4 

70  c.  c.  of  the  water  to  be  examined  for  hardness  should 
be  placed  in  a  stoppered  bottle,  holding  about  250  c.  c. 
The  standard  soap  solution  is  dropped  slowly,  by  means 
of  a  pipette  graduated  to  ^^ths  of  a  c.  c,  into  the  bottle, 
which  is  frequently  shaken  violently  to  note  the  amount 
of  soap  solution  necessary  to  create  a  persistent  lather. 
The  stopper  of  the  bottle  should  after  each  shaking  be 
removed  for  an  instant  to  allow  of  the  escape  of  the  car- 
bonic acid  gas  which  is  evolved.  If  a  water  is  so  hard 
that  the  addition  of  16  c.  c.  of  soap  solution  does  not 
produce  a  lather,  add  70  c.  c.  of  distilled  water,  and  mix. 
Then  continue  the  addition  of  the  soap  solution.  If  the 
dropping  of  soap  solution  be  proceeded  with  until  a  second 
1 6  c.  c.  be  consumed,  without  the  formation  of  a  perman- 
ent lather,  a  second  70  c.  c.  of  distilled  water  must  be 
added.  Suppose,  for  example,  19  c.  c.  of  soap  solution 
are  necessary : — 

19 

Deduct  for  liardness  of  each.  70  c.    c.   of  distilled 
water  employed         ......        1 

Degrees  of  liardness  .         .  .         .         .         .18 


DETERMINATION    OF    THE    HAEDNESS  141 

Wlien  a  water  is  very  hard  it  is  desirable  to  decant 
the  contents  of  the  bottle  into  a  larger  one  of  the  capacity 
of  about  500  c.  c.  To  know  the  quantity  of  carbonate 
of  lime,  or  other  hardening  and  soap-destroying  ingredi- 
ents contained  in  the  water,  subtract  1  degi'ee.  The 
water  just  cited  possesses  17  grains  of  carbonate  of  lime, 
or  salts  equivalent,  per  gallon.  If  a  water  is  found  to 
be  exceedingly  hard,  35  c.  c.  of  it  should  be  placed  in  the 
70  c.  c.  flask,  and  the  measure  filled  up  to  the  70  c.  c. 
mark  with  distilled  water.  The  quantity  of  soap  solution 
required  to  form  a  lather  with  this  mixture  must 
necessarily  be  doubled  in  recording  the  result.  A  rough 
and  ready  method  of  determining  the  hardness  of  very 
hard  waters  consists  in  measuring  10  c.  c.  of  the  water 
into  a  70  c.  c.  measure,  in  filling  up  the  same  with 
distilled  water,  and  multiplying  the  result  obtained  with 
the  soap  test  by  7.  It  is  necessary  to  chstinguish 
between  the  false  lather,  or  scum  produced  by  magnesian 
salts  present  in  the  water,  and  the  true  persistent 
lather. 

Boil  a  sample  of  the  water  for  about  a  quarter  of  an  Permanent, 
hour  (some  boil  for  half  an  hour),  and  when  cold  replace 
what  is  lost  as  steam  with  distilled  water.  Allow  any 
floating  particles  that  may  be  present  to  subside,  and 
examine  it  with  the  soap  test.  In  this  manner  the 
permanent  hardness  is  obtained. 

The  difference  between  the  'permanent  and  the  total  Temporary, 
hardness  is  termed  the  temporary  hardness. 

The  carbonate  of  lime  waters,  such  as  are  employed 
by  large  populations  in  the  chalk  districts  on  the  south 
coast  of  England,  lose  most  of  their  hardness  by  boiling. 
When  the  hardness  of  a  water  is  mainly  due  to  the  presence 
of  the  sulphates  of  lime  and  magnesia  and  chloride  of 
calcium,  boiling  makes  but  little  difference.  There  are 
some  grounds  for  thinking  that,  whilst  the  former  class  of 


142  DETEEMINATION    OF    THE    HAEDNESS 

Influence  on  wateis  are  not  deleterious  to  health,  and  in  certain  cases 
possess  remedial  properties/  the  latter  class  should  be 
objected  to  if  the  hardness  is  excessive.  Whilst  revising 
these  lines  I  have  been  engaged  in  the  examination  of  a 
spring  water  employed  by  villagers  living  on  the  new 
red  sandstone,  which  possesses  a  total  hardness  of  84° 
and  a  permanent  hardness  of  35°!  A  hard  water  will 
sometimes  produce  for  a  time  diarrhoea,  and  at  others 
constipation.  Dyspeptic  symptoms  are  often  complained 
of  by  those  who  have  been  accustomed  to  drink  soft 
water  on  coming  into  a  hard  water  district.  Lumbago 
and  suppression  of  urine  have  also  been  ascribed  to  the  use 
of  such  waters.  Dr.  Murray  of  Newcastle  -  on  -  Tyne 
gives  ^  a  terrifying  description  of  the  evils  resulting  in 
the  limestone  district  in  which  he  lives,  from  the  supply 
of  very  hard  waters. 

There  is  a  strong  feeling  in  the  medical  profession  of 
this,  and  especially  of  Continental  countries,  that  there  is 
a  connection  between  the  development  of  certain  calculous 
disorders,  goitre,  and  certain  forms  of  dyspepsia,  and  the 
employment  of  hard  waters,  but  no  e^^.dence  exists  of  a 
very  demonstrative  character  on  which  this  belief  rests. 
Certain  it  is  (1)  that  soft  waters  are  superior  to  hard  for 
domestic  and  manufacturing  purposes  ;  (2)  that  moderately 
hard  waters  are  more  palatable  than  very  soft  waters ; 
and  (3)  that  of  hard  waters  those  which  lose  much  are 
preferable  to  those  which  lose  little  of  their  hardness  by 
boiling. 

Independent  of  the  hygienic  aspect  of  the  question, 
the  waste  of  money  and  labour  is  not  to  be  overlooked 
in  the  case  of  town  supplies.     Each  degree  of  hardness 

^  To  the  hardness  of  the  water  supply  of  Clifton  is  attributed  its 
beneficial  effects  in  patients  suffering  from  chronic  diarrhoea. 

^  "  On  the  Influence  of  Lime  and  Magnesia  in  Drinking  Water  in  the 
Production  of  Disease."     Brit.  Med.  Journal,  September  28,  1872. 


DETEKMINATION    OF    THE    HARDNESS  143 

signifies  the  destruction  of  12  lbs.  of  the  best  hard  soap 
by  every  10,000  gallons  of  water.  If  soap  is  not 
employed  to  soften  a  hard  water,  fuel  and  carbonate  of 
soda  are  expensive  substitutes. 


CHAPTEE    VII 

THE    DETEEMIXATION    OF    THE    A]MOUXT    OF    ilAGXESIA, 
SULPHATES,  AND   PHOSPHATES 

A.  Magnesia — Sulphate,  Carl3onate,  and  Mtrate. 

B.  Sulphates     of    Lime,    Magnesia,    and    Soda    as 

Anhydrous  Sulphuric  Acid. 

C.  Phosphates. 

Salts  of  magnesia  and  sulphates  are  objectionable  in 
waters  if  in  excess.  A  good  water  does  not  possess 
more  than  traces  of  these  ingTcdients.  Their  estimation 
is  sometimes  required  when  the  question  is  raised  as  to 
the  wholesomeness  of  a  suggested  new  water  supply,  or 
as  to  the  comparative  merits  of  several  waters  from  which 
it  is  proposed  to  select  the  purest. 

It  cannot  be  otherwise  than  a  matter  of  astonishment 
that  so  little  attention  has  been  paid  in  the  past  to  the 
influence  on  health  of  the  earthy  constituents  of  waters 
that  do  not  come  under  the  designation  of  mineral  waters. 
Parisian  physicians,  although  li^dng  in  a  basin  of  sulphate 
of  lime,  appear  to  be  totally  ignorant  of  the  effects  of  this 
substance  on  health.  A  noticeable  feature  in  Dr.  Frank - 
land's  sanitary  analyses  is  the  complete  absence  of  all  re- 
ference to  the  amount  of  sulphates  in  a  water.  And  yet 
we  know  that  the  presence  of  an  excess  of  sulphates  in  a 
drinking  water  is  often  found  to  be  associated  with 
obscure    forms    of   dyspepsia,   with    obstinate    diarrhoea, 


MAGNESIA,  SULPHATES,  AND  PHOSPHATES  145 

alternating  with  constipation,  etc.  Selenitic  waters  in- 
jurionsly  '  affect  strangers  more  than  those  who  are 
habituated  to  their  use. 

Some  wells  furnish  water  so  purgative  as  to  preclude  Purgative 
the  possibility  of  employing  them  as  a  regular  water 
supply.  I  have  met  with  many  waters  of  this  kind  in 
Essex.  They  yield  sulphate  or  carbonate  of  magnesia.  I 
look  upon  them  in  this  county, — which  contains  ague, 
such  a  large  amount  of  liver  disorders,  hsemorrhoidal,  and 
other  malarial  affections, — as  mineral  waters  of  some 
value.  Holding  in  solution,  as  they  do,  not  only  a  pur- 
gative salt,  but  a  large  proportion  of  other  saline  matters, 
they  are  not  wholesome  waters  for  general  and  constant 
use.  In  localities  where  these  mineral  waters  exist,  the 
people  are,  for  the  most  part,  compelled  to  drink  pond 
water.  Malarial  affections  are  often  traceable  to  the 
employment  of  pond  water  for  drinking  purposes.  These 
aperient  waters  may  be  regarded  as  in  some  sense  the 
remedy  to  counteract  the  effects  of  the  poison,  for  they 
are,  in  all  probability,  of  great  service  in  congestion  of  the 
liver  and  in  hsemorrhoids,  by  relaxing  the  j)ortal  system 
of  vessels. 

A.  Magnesia — Sulphate,  Garhonate,  and  Nitrate. 

There  are  two  or  three  modes  of  making  approximative  Magnesia. 
calculations  as  to  the  amount  of  magnesia  in  a  water,  all 
being  similar  in  principle,  for  they  consist  in  precipitating 
the  lime  with  oxalate  of  ammonia,  and  then  estimating 
the  remaining  hardness  with  the  soap  test.  Boutron 
and  Boudet  take  200  c.  c.  of  the  sample  of  water  for 
examination,  and  add  to  it  the  smallest  quantity  of  a 
clear  concentrated  solution  of  oxalate  of  ammonia,  that  is 
sufficient  to  throw  down  all  the  lime,  and  then  they  allow 
the  mixture  to  stand  for  24  hours.  The  water  is  then 
boiled  for  half  an  hour,  and  filtered,  the   loss   being   re- 

L 


146         DETEEMIK'ATION    OF    AMOUNT    OF    MAGNESIA, 

placed  by  distilled  water.  When  cool  the  hardness  is 
determined  hj  the  soap  test,  and  the  number  of  degrees 
are  multiplied  by  "14,  to  bring  them  into  grains  per 
gallon.  Wanklyn  adopts  the  following  plan,-^  which  is 
more  rapid,  and  on  that  account  is  preferable,  if  equally 
accurate.  "Powdered  oxalate  of  ammonia  is  added  to 
the  w^ater  in  the  proportion  of  one  gramme  of  the  oxalate 
to  one  litre  of  the  water.  The  mixture  is  shaken  for  a 
minute,  and  filtered.  Having  convinced  oneself  of  the 
absence  of  any  free  acid  in  the  filtrate,  and  having  tested 
it  with  a  little  oxalate  to  make  sure  of  the  removal  of  the 
lime,  70  c.  c.  of  the  filtrate  are  triturated  with  the  soap 
test  to  ascertain  its  hardness.  If  there  be  any  degree  of 
hardness  beyond  the  one  degree  required  by  pure  water, 
magnesia  is  present.  Its  amount  may  be  calculated  by 
multiplying  the  remainder,  after  the  deduction  of  the  one 
degree,  by  the  fraction  ^^,  which  will  give  the  quantity 
of  carbonate  of  magnesia  per  gallon  of  water." 

It  should  never  be  forgotten,  in  employing  the  soap 
test,  that  a  certain  lapse  of  time  is  required  for  the  pro- 
duction of  the  lather  when  the  hardness  is  due  to 
magnesia,  whilst  in  that  occasioned  by  lime  the  lather  is 
immediately  observable. 

As  examples  of  the  amount  of  magnesia  in  potable 
waters,  the  following  analyses,  which  have  been  published 
by  Wanklyn  and  Playfair,  may  be  cited : — 


Name  of  Waters. 

Grains  per  Gallon. 

Total  Magnesia  in  terms  of 

Carbonate  of  Magnesia. 

Croydon  Water 

Sunderland  Water 

Thames 

New  River  Company 

Kent  Company 

Buxton  Water 

}J 

1-4 
9-46 
1-10 
•76 
1-56 
4-5 

1  02^.  eii. 


SULPHATES,    AND    PHOSPHATES  147 

B.  Anhi/drous  Sulphuric  Acid  {SO ■^)  from  Sulphates. 

The  amount  of  these  salts  may  be  roughly  estimated  suiph 
thus  : — Acidulate  a  large  test  tube  full  of  the  water  to  be 
examined  with  two  or  three  drops  of  hydrochloric  acid, 
and  then  add  a  small  quantity  of  a  solution  of  chloride 
of  barium.  If  there  is  a  precipitate,  the  amount  of 
sulphuric  acid  exceeds  one  grain  per  gallon.  If  there  is 
a  precipitate  after  standing,  there  is  at  least  1-|-  grain  per 
gallon.  3  and  4  grains  per  gallon  give  immediately  a 
turbidity  differing  in  degree  according  to  the  presence  of 
the  lesser  or  the  greater  amount.  Practice  with  waters 
to  which  known  quantities  of  sulphates  have  been  added 
will  soon  enable  the  Medical  Officer  of  Health  to  form 
rough  estimates.  When  it  is  desirable  to  calculate  the 
exact  amount  of  sulphuric  acid  as  sulphates,  it  is  conveni- 
ently done  in  either  of  the  following  ways  : — 

The  method  which  I  practise  is  the  following : — 
About  10  c.  c.  of  a  strong  solution  of  chloride  of  barium 
are  placed  in  a  beaker,  and  then  acidified  with  a  few 
drops  of  pure  hydrochloric  acid.  70  c.  c.  of  the  water 
to  be  examined  are  added,  and  the  contents  of  the  beaker 
are  boiled,  the  precipitate  being  allowed  to  settle  for  two 
hours.  Then  the  supernatant  liquid,  and  finally  the 
turbid  liquid  below,  are  filtered  off.  The  very  best 
Swedish  filter -paper  is  required,  otherwise  the  filter  will 
not  remove  entirely  the  sulphate  of  baryta.  The  pre- 
cipitate may  be  thoroughly  detached  from  the  sides  of  the 
beaker  by  the  aid  of  the  feather  of  a  quill  pen.  Wash 
out  the  beaker  with  hot  distilled  water.  The  washings 
are  to  be  passed  through  the  filter  until  the  fluid  that 
drops  from  the  funnel  leaves  no  residue  when  evaporated 
on  a  platinum  spatula  or  foil.  Allow  the  filter  to  drain, 
and  dry  it  gently  by  suspending  the  funnel  on  a  retort 
ring  at  some  distance  above  a  lighted  spirit  lamp.      Ignite 


148         DETEEMIXATIOX    OF    AMOUA^T    OF    MAG^'ESIA, 

the  filter  in  a  platinum  crucible  and  weigh.  The  differ- 
ence between  the  weight  of  the  empty  crucible,  and  the 
weight  of  the  crucible  and  its  contents  minus  the  weight 
of  the  ash  of  filter/  furnishes  a  number  of  milligrammes 
that  represent  grains  per  gallon  of  sulphate  of  baryta, 
which  should  be  recorded  in  terms  of  anhydrous  sulphuric 

acid,  e.g. — 

BaS04  Araouut  of  SO3 

' — , — '         BaS04  found.         ' — , — ' 

233       :        -004        ::        80 
80 


Crucible  and  its 

contents 

17-776 

Crucible     . 

17-770 

•006 

Deduct  weight  of 

ash  of  filter 

.     -002 

233Y3200/-001; 
/233   \ 


870 

-004  699 


171 


Besult. — Eather  more  than  1  milKgramme,  or  1'3 
gr.  of  anhydrous  sulphuric  acid  per  gallon. 

Houzeau's  method  ^  is  a  very  simple  and  perhaps  a 
more  rapid  one.  Prepare  a  solution  of  barium  chloride 
30-5  grammes  in  a  litre  of  distilled  water.  Obtain  a 
dropping  tube  which  furnishes  25  drops  for  each  c.  c. 
To  10  c.  c.  of  the  water  to  be  examined  after  acidifying 
with  one  drop  of  acetic  acid,  add  2,  4,  6,  8  or  10  drops 
of  the  barium  chloride  solution  by  means  of  the  dropping 
tube.  "Wait  for  3  minutes  and  if  a  deposit  is  formed, 
filter  the  liquid.  The  filtrate  is  to  be  treated  with  one  or 
more  drops  of  the  barium  chloride  solution.      If  a  deposit 

^  The  average  weiglit  of  ten  filter -paj^ers  should  be  estimated  and 
marked  on  the  packet.  The  labour  of  weighing  each  filter-paper  when 
employed  is  thus  avoided.  The  ash  is  about  \  per  cent  the  weight  of  the 
filter.  If,  for  example,  the  filter  weighs  400  milligi'ammes,  the  weight  of 
the  ash  will  be  2  milligrammes. 

^  Com2}tes  Rcndus,  Ixxxvii.  109. 


SULPHATES,    AND    PHOSPHATES 


149 


is  noticed  after  an  interval  of  3  minutes,  the  liquid  is 
again  poured  on  tlie  filter.  The  addition  of  diminishing 
quantities  of  the  barium  chloride  solution  is  repeated, 
until  the  filtrate  ceases  to  exhibit  the  faintest  cloud  after 
an  interval  of  3  minutes. 

Water  employed  10  c.  c.  +  1  drop  of  acetic  acid. 


Solution  of 

Cliloride  of 

Barium. 

First  Addition 

16  drops. 

Second 

5) 

2      „     . 

Third 

5) 

1   „  . 

Fourth 

5) 

1   „  . 

Fifth 

•>■> 

Total  drops  21 

(Abundant  deposit.) 
(Notable  turbidity.) 
(Feeble  turbidity.) 
(Very  feeble  turbidity.) 
(No  cloud  at  the  end 
of  3  minutes.) 


Total  drops  used  20 
Deduct  i  drop  from  fourth  addition      "5 


19 '5  drops. 


As  1  drop  =  "485  milligramme  of  anhydrous  sulphuric 
acid,  19 '5  drops  x '485  =  9"46  milligrammes. 

Hence  a  litre  of  water  contains  "946  grammes  or  6 6 '2 
grains  per  gallon  of  anhydrous  sulphuric  acid. 

The  following  list  (page  151)  will  afford  some  idea 
of  the  remarkable  differences  exhibited  by  various  kinds 
of  water  in  respect  to  the  amount  of  this  mineral 
ingredient. 

The  water  of  the  well  in  Hutton  is  avoided  by  the 
occupants  of  the  cottages  to  which  it  belongs,  on  account 
of  its  purgative  properties ;  whilst  that  from  the  well  at 
]\Iountnessing  is  occasionally  used  after  boiling.  Both  of 
these  wells  are  shallow,  and  are  situated  in  the  London 
clay  formation. 


150         DETEEMINATION    OF    AMOUNT    OF    MAGNESIA, 

Of  the  Metropolitan  waters,  that  of  the  Kent  Com- 
pany is  objected  to  hj  some  on  the  gromid  of  the  excess 
of  sulphates.  As  much  as  from  20  to  70  grains  of 
sulphates  per  gallon  have  been  found  in  some  drinking 
waters  in  Dublin  by  Dr.  Cameron. 

A  water  may  exhibit  a  large  amount  of  magnesia  and 
but  a  very  small  quantity  of  sulphates,  that  alkaline 
earth  being  in  the  form  of  carbonate,  as  for  example,  in 
the  waters  of  the  dolomite  formation. 

I  have  examined  well  waters,  pure  as  to  organic 
matter,  containing  4-|-  grains  per  gallon  of  sulphuric 
acid  in  the  form  of  sulphate  of  lime,  but  have  not  felt 
warranted  in  publicly  expressing  disapproval  of  the  use 
of  such  waters  for  drinking  purposes.  If  samples  of 
water  were  brought  to  me  in  order  that  I  might 
select  the  best,  I  should  certainly  at  the  outset  place 
a  water  containing  this  amount  of  sulphates  out  of 
competition. 

We  have  very  little  reliable  information  as  to  the 
effects  of  these  salts  in  drinking  water  on  the  health, 
but  that  they  must  have  a  very  decided  influence  admits 
of  no  doubt.  Can  it  be  a  matter  of  no  moment  from  a 
public  health  point  of  view  whether  people  are  drinking 
water  containing  100  grains  per  gallon,  as  at  IMount- 
nessing,  or  "5  of  a  grain  per  gallon,  as  at  Croydon,  of 
anhydrous  sulphuric  acid  from  sulphates  ? 

I  have  never  yet  seen  a  person  who  habitually 
employs  a  drinking  water  containing  a  large  amount  of 
sulphates  that  could  be  regarded  in  any  sense  by  a 
medical  eye  as  "  a  picture  of  health." 

C.  Fhosjjhatcs. 

hosijiiates.       When   we   remember   the   important   role   played   in 
the  human  organism  by  phosphates,  and  in  how  many 


SULPHATES,    AND    PHOSPHATES 


151 


Names  of  Waters. 


Sulphuric 
Acid  (SO3) 

from 
Sulphates. 

Grs.  per  Gal. 


Spiring   in  Admiral's  Park,    near   Chelmsford 

Essex  ..... 
Spring  in  Trinity  Lane,  Springfield,  Essex 
Spring  supplying  Grove  House,  Great  Baddow 

Essex  . 
iManchester  water 
Sunderland  water 
Croydon  water   . 
The  Rhine  at  Bonn 
Clareen  well,  Carrick-on-Suir 

Do.     river  do. 

Public  pump,  Waterford 
Pump  at  University  Club,  St.  Stephen's  Green 

Dublin 
Flooded  stream,  Holmfirth,  Yorkshire  Moors 
Carlisle  Waterworks 
AVater  of  shallow  well  in  Rose  Valley,  Brent 

wood  .... 
Water  of  deep  well,  Stanwix,  Carlisle 
Fountain  water  from  High  Town,   near  Halt 

whistle  .... 

Water    from    pump    in    Rutherford's    Court 

Stanwix,  Carlisle 
Pump  in  yard.  Prospect  Place,  Stanwix 
The  water  of  the  river  Ouse,  near  York,  on 

September  1,  1876 
The  .water  of  the  river  Ouse,  near  York,  on 

September  6,  1876      . 
Water  from  shallow  well  of  Jeffrey's  Endowed 

School,  Great  Baddow,  Essex 
Water  from  well  at   Brentwood  Hall,   Brent 

wood  ..... 
Water  from  Maldon  Waterworks 
Water  from  well  at  Little  Burstead 
Water  from  well  in  IMountnessing 
Water  from  well  in  Hutton 
Water  from  well  at  Hutton  Railway  Bridge 
/  Grand  Junction 
Thames      I  ^^^^^^  Middlesex      . 

Water      <  Southwark  and  Vauxhall  . 
Companies.    |  Chelsea 

\  Lambeth     . 

(  Kent 
Other       J  j^Tp^^,  Ri^-er 

^"™P^'"^^-   I  East  London 


1-.3 

5-8 

2-7 
1-1 

•93 

•5 

1-4 

1-2 

■9 

17-76 

49-4 
•87 
1-5 

4-54 
3^79 

•81 

10^57 
4-03 

4-3 

1-58 

16^36 

3-13 
4^51 
64^5 
100-0 
182-0 
2-7 
1-5 
1-47 
1-43 
1-52 
1-56 
2-82 
1-05 
1-59 


Pi'oposed 
as  public 
supplies. 


f  Closed,  as 
I    it  caused 
-I    diarrhoea 
I        and 
V  dyspepsia 


152         DETEEMINATION    OF    AMOUNT    OF    MAGNESIA, 

different  forms  they  occur  in  the  various  parts  of  the 
body,  it  is  a  matter  of  great  interest  to  study  the  relation 
between  the  use  of  waters  emanating  from  phosphatic 
strata,  and  the  condition  of  health  of  those  who  employ 
them.^ 

The  presence  of  an  excess  of  phosphates  when 
they  cannot  thus  be  accounted  for  is  often  due  to 
sewage  impregnation.  Tiemann  has  noticed  phosphates 
in  large  quantity  in  the  water  derived  from  marshy 
meadows. 

Mr.  Wanklyn  states,^  that  "  much  nonsense  has  been 
talked  about  phosphates  in  drinking  water."  "  Carbonate 
of  lime  and  phosphates  are  incompatible  in  drink- 
ing water."  Dr.  Dupre  has  affirmed  that  he  never 
examined  a  water  in  which  he  could  not  detect  phos- 
phoric acid.  In  Prof  Kubel's  Treatise  on  Water  Analysis, 
edited  by  Dr.  Tiemann,  is  to  be  found  the  follow- 
ing description  of  the  mode  of  testing  for  phosphoric 
acid :  "  Boil  the  water ;  the  precipitate  contains  the 
phosphates;  dissolve  this  precipitate  in  hydrochloric 
acid ;  evaporate  to  dryness,  and  heat  for  a  short  time 
a  little  over  212°  F.  Then  dissolve  in  a  little  hydro- 
chloric acid  and  water,  filter,  and  add  filtrate  to  a 
slightly  warm  clear  solution  of  ammonium  molybdate  and 
nitric  acid,  when  a  yellow  colour  and  precipitate  occur." 
The  nitric  acid  employed  should  be  of  the  greatest 
purity,    and    free   from   all   colour.       If   the   phosphates 

1  Mons.  Joly,  in  an  interesting  paper  to  one  of  tlie  Parisian  scientific 
societies,  says  that  the  importance  of  the  phosphates  in  the  animal 
economy  may  be  measured  by  tlie  fact  that  five  diff'erent  phosphates  are 
found  in  the  body :  in  the  red  blood  corpuscles,  phosphate  of  iron  ;  in  the 
liquor  sanguinis,  phosphate  of  soda  ;  in  the  nervous  system,  phosphate  of 
potash ;  in  the  muscles,  phosphate  of  magnesia  ;  and  in  the  bones, 
phosphate  of  lime.  In  each  case  the  phosphoric  acid  fulfils  very  difi"ereut 
functions,  according  to  the  bases  with  which  it  is  united. 

2  O}}-  cit. 


SULPHATES,  AND  PHOSPHATES  153 

are    in    very    small    proportion,    the    water    should    be 
concentrated  by  evaporation  previous  to  the  analysis. 

Dr.  Diipre  in  the  experiments  undertaken  by  the  Local 
Government  Board  in  1880-81,  already  referred  to,  em- 
ployed the  following  qualitative  method: — The  solution  of 
the  total  dry  residue  obtained  in  the  estimation  of  solids 
was  "warmed  in  nitric  acid,  after  filtration,  with  a  strongly 
acidified  solution  of  molybdate  of  ammonia." 

The   Society  of   Pubhc  Analysts   thus  describes  the  Method  of 
plan  which  it  recommends :   "  The  imited  total  residue  ^^'^L^^^i^^^ 

f  o  of  Public 

is  to  be  treated  with  a  few  drops  of  nitric  acid,  and  the  Analysts, 
silica  rendered  insoluble  by  evaporation  to  dryness.-^ 
The  residue  is  then  taken  up  with  a  few  drops  of  dilute 
nitric  acid,  some  water  is  added,  and  the  solution  is 
filtered  through  a  filter  previously  washed  with  dilute 
nitric  acid.  The  filtrate,  which  should  measure  3  c.  c, 
is  mixed  with  3  c.  c.  of  molybdic  solution  ^  gently 
warmed,  and  set  aside  for  15  minutes  at  a  temperature 
of  80°  F."  The  amount  of  phosphoric  acid  in  phosphates 
found  is  generally  recorded  either  as  "traces,"  "heavy 
traces,"  or  "  very  heavy  traces." 

^  Dr.  Asliby  suggests  the  removal  of  the  contents  of  the  platinum  dish 
to  a  porcelain  one  before  evaporation  to  dryness,  as  this  metal  is  dissolved 
in  the  presence  of  chlorides. 

^  "  One  part  pure  molybdic  acid  is  dissolved  in  4  parts  of  ammonia 
(sp.  gr.  •960).  This  solution  after  filtration  is  poured  with  constant  stir- 
ring into  15  parts  of  nitric  acid  of  1-20  sp.  gr.  It  should  be  kept  in  the 
dark  and  carefully  decanted  from  any  precipitate  Avhich  may  form." 


CHAPTEE   VIII 

THE    DETEKMINATIOI^    OF    POISONOUS    METALS 

The  poisonous  metals  which  water  analysts  are  called 
upon  to  consider  are  lead  and  copper.  The  occurrence  of 
arsenic,  zinc,  tin,  and  barium,  etc.,  in  drinking  water,  is 
so  rare  as  to  hardly  merit  the  attention  of  the  health 
officer.  In  the  Afghanistan  campaign  of  1839  there 
was  a  large  mortality  amongst  the  British  detachment 
stationed  at  Ali  Musjid,  which  was  ascribed  to  the  strong 
impregnation  of  the  water  with  antimony. 

Lead  and  copper  are  usually  the  poisonous  metals, 
especially  the  former,  with  which  waters  are  liable  to 
be  contaminated.  A  water  sometimes  contains  iron, 
which  is  of  course  undesirable  in  all  cases,  except  for 
medicinal  purposes,  and  hurtful  in  some. 

Place  7  0  c.  c.  of  water  to  be  examined  in  a  porcelain 
dish,  and  stir  it  with  a  glass  rod  moistened  with  sul- 
phuret  of  ammonium.  Note  whether  or  not  there  be 
any  coloration.  If  so,  it  may  be  owing  to  a  sulphuret 
of  iron  or  lead,  or  of  copper.  If,  on  adding  two  or 
three  drops  of  hydrochloric  acid,  the  brown  colour  dis- 
appears or  diminishes,  iron  is  present,  for  the  hydro- 
chloric acid  dissolves  the  sulphuret  of  iron.  If,  on  the 
other  hand,  the  colour  does  not  vanish  or  diminish  on 
this  addition,  lead  or  copper  is  present.  It  matters  not 
which,  for  both  are  equally  injurious.      "Wanklyn   writes, 


DETERMINxVTION    OF    POISONOUS    METALS  155 

"  If  there  be  coloration,"  on  introducing  the  sulphuret  of 
ammonium,  "  it  should  only  be  ju.st  visible,  and  on  adding 
two  or  three  drops  of  hydrochloric  acid,  it  ought  to 
vanish  absolutely."  AVater  which  answers  to  this  test 
in  a  satisfactory  manner  is  registered  as  sufficiently  free 
from  poisonous  metals,  and  water  which  does  not,  is  to 
be  condemned  as  contaminated  with  metallic  impurity. 
If  the  quantity  of  either  of  these  metals  in  a  water  be 
required,  it  is  necessary  to  employ  standard  solutions, 
containing  one  milligramme  of  each  metal  in  each  cub. 
cent,  of  its  solution  (made  by  dissolving  1'66,  3 "9  3,  and 
4' 9  6  grammes  of  crystallized  acetate  of  lead,  or  sulphate 
of  copper  or  proto-sulphate  of  iron  in  a  litre  of  distilled 
water);  and,  if  we  desire  to  ascertain  whether  lead  or 
copper  be  present,  it  is  needful  to  operate  on  a  larger 
quantity  of  water,  and  to  work  according  to  the  directions 
in  that  distinguished  chemist's  exhaustive  treatise  on 
water  analysis. 

The  above  simple  mode  of  testing  for  poisonous 
metals -is  sufiicient  for  the  Medical  Officer  of  Health,  for 
it  enables  him  to  say  that  a  water  contains  less  than 
jljth  grain  of  lead  or  copper  per  gallon,  an  amount  which 
should  condemn  a  drinking  water.  Water  is  considered 
to  be  admissible  for  domestic  purposes  if  containing 
"I"  grain  of  iron  per  gallon,  but  the  presence  of  one  grain 
of  this  metal  per  gallon  is  deemed  to  be  sufficient  to 
justify  its  rejection.  The  French  chemists  consider  that 
the  amount  of  iron  should  not  exceed  '2 1  grain  per  gallon 
in  a  potable  water. 

Medical  literature  teems  with  instances  of  poisoning 
by  lead  and  copper.  It  is  curious  to  note  the  timidity 
with  which  Cornish  miners  look  upon  waters  issuing  from 
strata  known  to  contain  metals,  and  how  they  altogether 
ignore  the  risk  of  drinking  water  contaminated  with  filth 
of  the  filthiest  description. 


156  DETEEMIXATIOX    OF    POISONOUS    METALS 

Lead.  LccLcl. — The  actlon  of  different  kinds  of  water  on  lead 

forms  a  very  large  subject,  -whicli  cannot  here  be  even 
briefly  adverted  to. 

Lead  poisoning  sometimes  occurs  when  the  water  of  a 
well  is  verj  soft  and  free  from  saline  ingredients,  in 
consequence  of  its  action  on  the  leaden  pipe  that  descends 
into  it  from  the  pump,  and  through  which  it  is  raised. 
This  danger  does  not  exist  in  the  case  of  highly  saline 
waters,  for  the  salts  so  encrust  the  leaden  pipe  as  to 
prevent  the  solution  of  the  lead  by  the  water.  Lead 
pipes  should  never  be  employed  in  wells.  It  has  been 
pointed  out  to  me  by  Dr.  Ashby  that  waters  from  the 
oolitic-limestone  district  in  which  he  lives  do  not  act  on 
lead,  owing  to  the  protective  action  of  the  traces  of  phos- 
phoric acid  contained  in  them. 

Several  of  the  Yorkshire  cities,  such  as  Sheffield, 
Huddersfield,  Eochdale,  and  Keighley,  are  reported  to 
suffer  fi'om  impregnation  of  their  water  supjDly  with  more 
Sheffield  or  Icss  lead.  A  very  excellent  report  on  that  of  Sheffield 
siiMi^y  has  recently  been  issued  by  Dr.  Sinclair  A^Tiite,  the 
Medical  Officer  of  Health,  who  found  that  a  portion  of 
it  furnished  by  certain  springs  supplied  to  a  particular 
section  of  the  city  was  acid  and  contained  an  amount  of 
lead  varying  from  "07  to  '7  grain  per  gallon,  from  which 
the  water  supply  of  the  remainder  of  the  city  (derived 
from  another  source)  was  free.  He  attril:)utes  the  acidity 
either  to  ulmic  and  humic  acids  from  the  decomposition 
of  peat,  or  to  sulphuric  acid  produced  by  the  oxidation  of 
the  iron  pyrites  contained  in  the  shale  underlying  the 
moorland  peat,  from  which  the  former  or  "  high  level " 
supply  proceeds.  He  suggests  that  a  protective  property 
be  imparted  to  the  water  by  passing  it  for  fifteen  minutes 
over  small  fragments  of  limestone. 

An  approximation  to  the  proportion  of  lead  present  in 
a  water  may  be    arrived   at   by  means    of  ]Mr.  Wynter 


DETERMINATIOISr    OF    POISONOUS    METALS  157 

Blytli's  cocliineal  colour  test/  but  the  exact  quantity  is 
calculated  by  the  author  in  the  following  simple  manner. 
Take  two  Nessler  glasses  graduated  into  c.  c.  and  pre- 
cisely alike.  Place  70  c.  c.  of  the  water  under  examina- 
tion in  one,  and  50  or  60  c.  c.  of  distilled  water  into  the 
other.  Let  them  rest  on  a  wdiite  slab.  Introduce  a 
glass  rod  dipped  in  ammonium  sulphide  into  each.  If  any 
lead  is  present  in  the  water,  a  brown  colour  is  developed. 
]\Iatch  its  depth  by  adding  to  the  distilled  water,  by 
the  help  of  a  burette  graduated  into  cub.  cents.,  a 
standard  solution  of  acetate  of  lead  (1'66  grammes  of 
crystallized  acetate  of  lead  to  1  litre  of  distilled  water 
of  which  1  c.  c.  =  1  milligramme  of  lead)  in  sufficient 
quantity  to  exactly  match  the  tint.  Bring  the  volume 
of  the  diluted  standard  up  to  the  70  c.  c.  mark,  and  then 
make  a  final  comparison.  The  number  of  cub.  cents, 
of  the  standard  lead  solution  employed  represent  the 
number  of  grs.  of  lead  in  a  gallon  of  water. 

Iron. — The  plan  recommended  by  Dr.  Tidy^  for  the  iron, 
detection  of  iron  and  for  ascertaining  the  form  in  which 
it  is  present  is  as  follows  : — Fill  3  tubes  (each  2  ft.  long)  cr.  Tidy's 
with  the  suspected  water ;  into  one  («)  place  a  drop  or  jxe^hof'^ ' 
two  of  a  solution  of  ammonic  sulphocyanide,  which  gives 
a  blood-red  colour  with  ferric  salts ;  to  the  second  (&)  add 
first  of  all  a  few  drops  of  nitric  acid  (to  oxidize  ferrous 
salts  if  present)  and  then  a  few  drops  of  the  ammonic 
sulphocyanide  solution.     Compare  the  tint  depths  of  these 
tubes  with  one  another,  and  of  both  with  the  pure  water 
tube  {c).      If  no  red  tint  is  observable  in  {a)  tube,  but  is 
developed   in  (h)  tube,  iron  is   present   in   the   form  of 
ferrous  salts. 

Dr.  Franklin  Parsons  suggests  the  following  method 
of  rapidly  estimating  small  quantities  of  iron : — "  Take 
the  residue  of  70  c.  c.  used  in  the  determination  of  the 

1  AscUpiad,  January  1SS4,  p.  91.  "  Op.  cit. 


158  DETERMIXATIOX    OF    POISOXOCS    METALS 

Dr.  F.         solids,  ignite  it  gently  (a   strong  beat  renders  the   ferric 
Parson's      gxide  insoluble)  dissolve  it  in  a  little  warm  nitric  acid 

Quantitatu'e  ' 

Method  (wliicli  oxidizes  the  iron  to  the  ferric  state)  dilute  to  about 
25  c.  c.  with  water,  and  add  a  single  drop  of  a  solution 
of  ferrocyanide  of  potassium.  The  blue  colour  resulting 
is  gauged  by  comparison  with  that  of  a  standard  solution 
in  the  same  way  as  ammonia  is  estimated  colorimetrically. 
The  standard  solution  is  easily  made  by  dissolving  one 
decigramme  of  iron  wire  in  dilute  sulphuric  acid,  adding 
a  few  drops  of  nitric  acid  and  boiling ;  when  cold  it  is  to 
be  diluted  to  1 0  0  c.  c.  Each  c.  c.  contains  a  milligramme 
of  ii'on.  This  solution  is  kept  in  stock.  A-N^ien  required 
1  c.  c.  of  this  solution  is  run  into  a  100  c.  c.  test  mixer, 
diluted,  a  drop  of  ferrocyanide  solution  added,  and  the 
test  mixer  filled  up  to  100  c.  c.  Two  cylinder  glasses 
of  equal  diameter  are  then  taken  and  placed  on  a  sheet 
of  white  paper ;  in  one  the  dissolved  water  residue  is 
placed  and  treated  with  ferrocyanide  solution ;  into  the 
other  is  poured  as  much  of  the  standard  blue  solution 
from  the  test  mixer  as  will  produce,  when  looked  down 
through,  an  equal  shade  of  colour.  The  amount  is  known 
by  reading  the  graduations  on  the  test  mixer,  each  c.  c.  corre- 
sponding to  "01  grain  of  iron  per  gallon:  "05  gTain  pev 
gallon  may  in  this  way  be  estimated  in  the  residue  of  70 
c.  c.  of  water.  Prussian  blue  in  solutions  so  dilute  precipi- 
tates very  slowly,  so  that  the  same  standard  solution  will 
serve  for  several  determinations.  The  solution  of  ferro- 
cyanide need  not  be  of  any  definite  strength,  but  had 
better  be  somewhat  dilute :  enough  must  of  course  be 
added  to  combine  with  all  the  iron  present,  but,  on  the 
other  hand,  care  must  be  taken  not  to  add  a  large  excess, 
as  it  gives  a  yellow  tinge  to  the  solution  which  interferes 
with  the  correct  estimation  of  the  blue."  The  question, 
of  course,  arises  as  to  the  practical  utility  of  making  such 
minute  determinations  of  iron  in  a  sanitary  analysis. 


DETERMINATION    OF    POISONOUS    METxVLS  159 

If  we  have  occasion  to  ascertain  whether  or  not  a 
water  defiled  by  mines  or  manufactories  contains  arsenic, 
-|-  litre  of  such  water,  being  rendered  slightly  alkaline  by 
hydrate  of  soda  or  potash  free  from  arsenic,  should  be 
evaporated  to  dryness.  The  residue  having  been  digested 
in  strong  hydrochloric  acid  should  be  poured  into  the  ap- 
paratus described  on  page  346  and  depicted  in  Fig.  40,  and 
examined  by  Marsh's  test  or  by  Davy's  method,  page  347. 

Co]3])eT. — The  amount  of  this  metal  in  a  water  is  copper. 
usually  determined  by  a  colorimetric  method,  which  is 
conducted  in  a  manner  precisely  sunilar  to  those  em- 
ployed in  the  other  volumetric  processes  already  described. 
The  depth  of  brown  or  chocolate  colour  produced  by  a 
4  per  cent  aqueous  solution  of  ferrocyanide  of  potassium 
in  a  water  containing  copper,  is  imitated  by  that  dis- 
played in  an  equal  volume  of  distilled  water  to  which 
different  quantities  of  a  standard  solution  of  sulphate  of 
cojDper  (3-93  grammes  in  1  litre  of  distilled  water,  of 
which  1  c.  c.  =  1  milligramme  of  copper)  have  been 
added.  The  amount  of  standard  solution  of  sulphate  of 
copper  consumed  of  course  furnishes  the  datum  on  which 
rests  the  simple  calculation  as  to  the  amount  of  copper 
present  in  the  sample  of  water.  Mr.  Wynter  Blytli 
suggests  the  addition  of  a  solution  of  nitrate  of  ammonia, 
which  renders  the  reaction  much  more  delicate. 

Zinc. — A  case  has  been  reported^  by  the  Medical  zinc. 
Officer  of  Health  of  Llanelly  of  the  impregnation  of  the 
public  water  supply  to  the  village  of  Cwmfelin  with  zinc 
derived  from  the  galvanized  iron  water  pipes.  The  total 
solids  being  18-9  grains  per  gallon,  6-41  grains  of  them 
consisted  of  zinc  carbonate.  It  seems  that  pure  zinc  is 
easily  dissolved  l;)y  water  through  which  a  current  of  oxy- 
gen and  carbonic  acid  gas  is  ]3assed.  This  metal  may  be 
detected  by  evaporating  to  dryness  a  little  of  the  water  on 

^^Lancct,  March  1,  1884,  p.  403. 


IGO 


DETEKMINATION    OF    POISONOUS    METALS 


Should 
■nater 
stored 
in  leaden 
cisterns  be 
used  for 
drinking 
purposes? 


a  piece  of  platinum  foil ;  when  the  volatile  matter  is  burnt 
away  the  residue  will  be  found  to  be  yellow  when  hot,  and 
white  when  cold.  This  residue,  transferred  to  a  piece  of 
charcoal  and  treated  with  a  solution  of  nitrate  of  cobalt, 
yields  a  green  colour  when  heated  in  the  outer  flame  of 
the  blow-pipe. 

My  experience  teaches  me  the  wisdom  and  expediency 
of  recommending  a  strict  avoidance  for  drinking  purposes 
of  all  water  that  has  been  stored  in  leaden  cisterns,  or 
has  otherwise  rested  for  some  time  in  contact  with  lead, 
until  we  'possess  data  of  a  less  contradictory  and  more 
definite  description  than  at  present  as  to  the  influence  of 
various  kinds  of  water  under  different  circumstances  on 
tills  metal. 


CHAPTEE    IX 

MICROSCOPIC    EXAMINATION    OF    A    WATER. 

A.  Tlie  Examination  of  a  Water  free  from  Deposit. — The 
approximative  estimate  of  the  number  of  micro-organisms 
and  the  diagnosis  of  tlie  kind,  whether  bacteria,  bacilli, 
micrococci,  vibrios,  spirillse,  etc.  may  be  accomplished  by 
the  aid  of  a  microscope  by  making  {a)  a  cover  glass  pre- 
paration and  (b)  a  "  drop  culture." 

(a)   Cover   glass    preparations. — The    author    finds    it  cover  glass 

.  prepara- 

useful  to  examine  a  water  in  the  manner  practised  bytions. 
Xoch  as  described  by  Prof.  Warden.^  With  a  glass 
rod  sterilized  by  passing  it  several  times  through  a  flame 
of  a  Bun  sen's  burner,  a  drop  of  the  water  to  be  examined 
is  placed  on  a  clean  cover  glass,  which  is  allowed  to  dry 
under  a  bell  glass.  "  When  the  water  has  evaporated,  the 
edge  of  the  cover  glass  being  held  by  a  pair  of  pincers, 
and  the  side  containing  the  residuum  being  upwards,  the 
cover  glass  is  rapidly  drawn  three  times  with  a  downward 
motion  through  the  colourless  flame  of  a  Bunsen's  burner 
or  through  a  large  spirit  flame."  The  cover  glass  still  held 
by  the  pincers  is  then  flooded  with  methyl  blue  solution,^ 

1  Op.  cit. 

^  Mode  of  Preparation. — Methyl  blue,  2  grammes  rubbed  in  a  mortar 
with  10  c.  c.  of  absolute  alcohol  to  which  90  c.  c.  of  distilled  water  is  gradu- 
ally added.  The  mixture  is  filtered  into  a  bottle  provided  with  a  perfor- 
ated cork  carrying  a  pipette,  by  means  of  which  a  small  quantity  can  be 
removed  as  required.  A  small  fragment  of  camphor  should  be  placed  in 
the  filtered  solution. 

M 


cultures. 


162  MICEOSCOPIC    EXAMINATION    OF    A    WATER 

which  is  allowed  to  act  for  about  3  minutes.  The  dye 
is  then  washed  off  by  a  gentle  stream  of  water.  The 
cover  glass  should  be  allowed  to  dry  under  a  bell  glass 
and  finally  mounted  in  Canada  balsam  when  it  is  ready 
for  the  microscope.  The  easiest  plan,  perhaps,  is  to  kill 
and  precipitate  the  microbes  by  adding  to  the  water  a 
1^  per  cent  solution  of  osmic  acid,  in  the  proportion  of 
1  c.  c.  of  the  latter  to  30  or  40  c.  c.  of  the  former. 
Drop  (b)  "  Drop  cultures  "  have  been  recommended  by  Dr.  E. 

Crookshank^  as  suitable  for  the  study  of  the  life  history 
of  the  micro-organisms  in  water.  He  gives  the  following 
directions  for  their  management : — "  Clean  an  excavated 
microscope  slide  and  sterilize  it  by  holding  it  cupped  side 
downwards  in  the  flame  of  the  Bunsen's  burner.  A  ring 
of  vaseline  is  painted  around  the  excavation.  A  clean 
cover  glass  is  sterilized  in  the  same  manner.  With  a 
platinum  needle  bent  at  its  extremity  into  a  minute  loop 
or  ring  (which  has  been  sterilized  by  holding  it  in  the 
flame)  transfer  a  drop  of  sterile  bouillon  ^  to  the  cover 
glass  and  this  drop  is  inoculated  by  touching  it  with 
another  sterilized  platinum  needle  charged  with  the  water 
under  examination."  The  slide  is  then  inverted  and 
placed  over  the  cover  glass,  so  that  the  drop  will  come 
exactly  in  the  centre  of  the  excavation,  and  is  gently 
pressed  down.  On  turning  the  slide  over  again  the  cover 
glass  adheres,  and  an  additional  layer  of  vaseline  is  painted 
around  the  edge  of  the  cover  glass  itself  The  slide  must 
if  necessary  be  placed  in  the  incubator  {vide  fig.  8,  page  82). 
In  this  manner  the  gradual  growth  of  a  micro-organism 
can  be  watched. 

B.  Examination  of  Deposit. — The  best  and  most  simple 

^  Introduction  to  Practical  Bacteriology. 

2  Made  in  the  same  manner  as  Koch's  nutrient  jelly  {vide  p.  76)  with 
the  omission  of  the  gelatine  and  salt.  The  use  of  the  hot  water  jacket  is 
not  needful  during  its  filtration. 


MICROSCOPIC    EXAMINATION    OF    A    WATER  163 

mode  of  examining  the  deposit  from  any  sample  of  water 
is,  first,  to  allow  suspended  matters  to  subside  in  the 
sample  bottle  ;  and  secondly,  to  decant  the  greater  part  of 
the  water,  and  pour  that  at  the  bottom  of  the  bottle 
containing  the  sediment  into  a  conical  glass.  After 
subsidence  a  drop  of  the  water  containing  the  de- 
posit may  be  removed  by  means  of  a  pipette  to  the  cell 
of  a  microscope  slide  and  be  allowed  to  evaporate,  or  the 
drop  may  be  immediately  covered  with  a  thin  glass,  the 


Fig.  15. 
Conical  Glass  and  Pipette. 

excess  being  removed  with  blotting-paper,  and  examined. 
If  a  water  possesses  much  turbidity  this  transfer  to  a 
conical  glass  is  of  course  unnecessary.  If  the  amount  of 
sediment  procured  in  this  way  is  practically  nil,  the  greater 
part  of  the  water  in  the  conical  glass  should  be  poured 
away,  and  that  remaining  in  the  angle  of  the  cone  should 
be  transferred  to  a  burette  similar  to,  bvit  of  much  larger 
diameter  than,  that  depicted  in  Fig.  3.  After  subsidence 
the  solid  bodies  may  easily  be  removed  in  single  drops  of 
fluid  on  to  microscope  slides.     In  the  microscopic  exam- 


164  MICROSCOPIC    EXAMINATION    OF    A   WATER 

ination  of  waters  we  require  a  5-incli  object  glass,  a 
Powell  and  Lealand  or  Zeiss'  oil  immersion  -J^-tli-inch  object 
glass,  and  an  Abbe's  condenser.  A  polariscope  is  a  useful 
addition  for  the  diagnosis  of  starch  granules. 

The  deposit  of  every  water  is  treated  by  the  French 
with  the  following  reagents :  a  solution  of  iodine  for  the 
detection  of  starch  ;  a  solution  of  carmine  in  glycerine  and 
alcohol,  which  imparts  to  the  nuclei  of  cells  a  red  stain ; 
and  methyl  violet  for  bacteria.  The  tremulous  molecular 
or  Brownian  movement  of  inorganic  particles,  in  which 
there  is  no  change  of  position,  must  not  be  confounded 
with  the  motions  of  micro-organisms.  Liquor  potassae 
and  strong  acetic  acid,  which  either  alter  or  remove  fatty 
and  albuminous  granules,  do  not  affect  micro-organisms 
such  as  micrococci,  etc. 
Inorganic  The  microscopic  examination  of  the  floating  particles 

particles,  gometimcs  seen  in  water,  will  often  afford  valuable  infor- 
mation concerning  it  where  there  is  any  doubt  as  to  its 
quality.  Mineral  gritty  matters,^  silt  of  clay,  and  sandy 
particles,  may  be  the  cause  of  persistent  and  unaccount- 
able diarrhcea,  which  medicines  will  only  temporarily  re- 
lieve. New  comers  to  a  place  where  such  water  is  used 
often  suffer.  Those  who  drink  such  waters  long  become 
generally  unaffected  by  these  intestinal  irritants.  Chalky 
particles  are  dissipated  by  the  addition  of  a  little  mineral 
acid,  whilst  the  other  inorganic  matters  apt  to  occur  in 
drinking  waters  are  unaffected  thereby. 

The  existence  of  animal  life  in  a  water  affords  good 
evidence  in  itself  of  the  presence  of  a  tangible  amount 
of  organic  matter,  alias  filth,  whether  it  be  the  micro- 
organism seen  in  the  fairly  pure  waters  supplied  by  the 
majority  of  the  London  companies,  with  an  average  of 

^  The  mountain  dysentery  prevalent  in  certain  districts  in  India  has 
been  shown  to  be  due  to  the  employment  of  drinking  water  containing  in 
suspension  minute  pai'ticles  of  mica. 


MICEOSCOPIC    EXAMINATION    OF    A    WATEE  165 

about  "08  milligramme  of  albuminoid  ammonia  per  litre, 
or  the  various  humble  animal  organisms  of  pond  water, 
with  its  "38  milligramme  of  albuminoid  ammonia  per  litre. 
These  little  creatures  feed  and  flourish  on  what  we  call  or- 
ganic matter,  and  in  perfectly  pure  water  they  cannot  live. 

Pasteur  has  shown  that  there  are  certain  waters  coming 
from  deep-seated  springs  that  are  destitute  of  organic  life, 
and  are  sterile ;  but  9  9  out  of  every  100  waters  contain  a 
greater  or  less  number  of  micro-organisms,  and  the  great  ma- 
jority of  these  9  9  waters  exhibit  organisms  of  much  larger 
dimensions  than  those  which  are  known  as  micro-organisms. 

The  kind  of  animal  and  vegetable  life  seen  in  water  Description 
gives  a  certain  clue  to  the  description  of  water  we  are^^^'^^^g^. 
examining.      Speaking  generally,  the  infusoriee,  the  con- tawe  life 
fervse,  and  vorticellse,  are  the  inhabitants  of  the  least  pure  ascertained 
of  spring  waters;  then  come  the  diatoms-^  and  desmids ; 
entomostraca   or  water  fleas  ^  are  seen  in  spring  ponds, 
lochs,  and  impounded  waters  ;  euplota  and  fungoid  growths, 
etc.,   abound    in    pond    and    ditch  waters,    and   in   well 
water  polluted  with  filth ;  whilst  bacteria  and  paramecia 
and    spirilla    are    prominent    in    sewage-polluted    water. 
There  is  no  evidence  to  show  that  those  low  forms  of  life, 
commonly  known  as  the  fungi,  are  in  themselves  hurtful 
if  taken  into  the  system,  although  their  appearance  is  an 
unfavourable  symptom.      It  is  highly  probable,  however, 
that  the  poisons  of  several  of  the  zymotic  diseases  are 

^  Some  erroneously  believe  that  the  presence  of  diatoms  is  an  indication 
of  evil  omen.  The  Bristol  water,  which  is  a  fairly  good  one  {vide  p. 
97),  contains  a  quantity  of  diatoms  of  different  kinds  of  which  I  have 
made  drawings.  Sometimes  when  very  abundant  they  present  the  appear- 
ance of  an  exceedingly  faint  milky  cloud  settling  doT\Ti  to  the  bottom  of 
the  vessel  which  holds  the  water. 

^  To  the  presence  of  vast  numbers  of  dead  entomostraca  the  fishy  odour 
noticed  by  passengers  in  the  steamboats  on  the  Lake  of  Geneva  has  been 
attributed.  These  minute  crustaceans  secrete  an  oily  substance  under 
their  carapaces,  to  which  certain  bad  tastes  of  public  water  supplies  have 
been  ascribed  (  Water  Siqyply — Chemical  and  Sanitary,  by  Prof.  Nichols). 


166  MICKOSCOPIC    EXAMINATION    OF    A    WATER 

either  identical  with,  or  are  products  of,  certain  micro- 
organisms (which  can  be  distinguished  by  their  appearance 
or  behaviour  from  one  another)  or  find  a  congenial  soil 
amongst  such  organisms,  which  act  as  carriers,  to  which 
they  attach  themselves,  and  amongst  which  they  multiply. 
Dr.  Frankland  and  his  followers  regard  the  presence 
of  anything  like  a  moving  organism  in  a  water  as  a  danger- 
signal,  for  the  reason  that,  if  the  poisons  of  such  diseases 
as  cholera  and  typhoid  fever  attach  themselves  to  particles 
of  organic  matter,  and  can  operate  in  inconceivably  minute 
quantities,  as  is  generally  believed,  there  is  a  possibility 
of  the  disease  ferment  or  germ  of  such  maladies  accom- 
panying elementary  forms  of  life.  Dr.  Mills  of  Glasgow, 
following  Dr.  Frankland's  example  as  to  the  metropolitan 
waters,  frequently  refers  in  his  public  reports  to  the 
presence  of  living  organisms  in  the  water  of  Loch  Katrine 
as  detracting  from  its  purity. 

DESCRIPTION  OF  PLATES  OF  MICROSCOPIC  OBJECTS 
FOUND  m  DRINKING  AVATER.i 

1.  Actinophrys  Sol.     Order — Radiolaria.     22.  Tabellaria     floccosa.     Family  —  Diato- 

2.  Algaj,  with  bacteria  and  diatoms.  macece. 

3.  Bacillus.  )  ^      .,       ^    ^    .  23.  Chsetophora  Elegans. 

,    „     ,     .      [-Family — Bacteriacece.  n^    -n     i     ■        ^i         t  ^ 

4.  Bacteria.  )  24.  Euglenia.     Class— Infusoria. 

5.  Amoeba.     Class— Rhizopoda.  25.  Anguillula.     Order — Nematoda. 

6.  VorticellK.     Class — Infusoria.  26.  Rotifera. 

7.  Ova  of  Entozoa.  27.  Cyclops    Quadricornis.      Order  —  Cope- 

8.  Euplotes  Vannus.     Class — Infusoria.  poda.     Sub-class — Entomostraca. 

9.  Paramecium.     Class — Infusoria.  28.  Cosmarium      Margaritiferum.      Family 

10.  Young  Filaria,  or  thread  worm.s.  — Desmidiacece. 

11.  Confervte.  29.  Diatoma  Vulgare. 

12.  Muscular  fibre.  .SO.  Diatom. 

13.  Spirillum.     Family — Bacteriacece.  31.  Fungi. 

14.  Hair  (human).  32.  Vegetable  cellular  tissue. 

15.  Linen  fibre.  33.  Scenedesmus.    Family — Desmidiacece. 
10.  Cotton  fibre.  34.  Daphnia      pulex.      Order  —  Cladocera. 

17.  Mineral  particles.  Sub-class — Entomostraca. 

18.  Fragment  of  deal  wood.  35.  Micrococcus.    Family — Bacteriacece. 

19.  Stomata  of  leaf.  36.  Infusoria. 

20.  Epithelial  scales.  37.  Ova  of  Nais.     Class — Annelida. 

21.  Closteriura  moniliformis.  Family —    38.  Vegetable  debris. 

Desmidiaf.ece. 

■^  The  objects  are  depicted  as  magnified  by  means  of  glasses  of  dif- 
ferent powers,  but   this  is   unimportant.      My  sole   desire  is   to  fix  on 


MICROSCOPIC   OBJECTS  Y  <\l 

\ 

lo  folloyi  (', 


TO  IN  DRmKING  WATER 


MICROSCOPIC    EXAMINATION    OF    A    WATER  1G7 

The  public  water  supply  of  Llandudno  was  condemned 
some  years  ago  by  the  late  Mr.  Wigner,  the  analyst,  on 
the  ground  of  its  unfavourable  appearance  when  examined 
by  the  microscope,  for  the  results  of  his  chemical  study  of 
it  would  not  certainly  warrant  a  censure. 

Free  Ammonia  .  -068  ]  ,^.,1.  t^ 

.,,     .  .  „„     >  Milligramme  per  litre. 

Alb.  Ammonia  .  -06    j  °  '- 

Nitrogen  as  Nitrates  and 

Nitrites  .  .  "24  gr.  per  gallon. 

Another  class  of  scientific  men  regard  insects  in  water 
as  scavengers  that  assist,  like  plants,  in  its  purification,  and 
place  the  greatest  reliance  on  those  great  natural  purifying 
processes  of  oxidation  and  dilution,  the  existence  of  which 
we  are  all  too  prone  to  forget.      They  urge  that  there  is 
no  reason  for  supposing  that  an  animal  poison  will  attach 
itself  to  an  infusorian  animalcule,  but  rather  to  organic 
matter  in  a  state  of  putrefactive  change,  and  that  there 
exist  good  grounds  for  thinking  that  an  animal  poison 
when  enormously  diluted  with  water,  becomes  harmless,  as  An  animal 
it  does  when  very  freely  mingled  with  the  other  medium,  ^°|,^j.^^^^j^° 
air.      Personally  I  feel  a  greater  sympathy  with  the  latter  diluted  with 
than  with  the  former  class,  although  there  can  be  no  doubt  becomes  in-' 
but  that  when  Dr.  Frankland  sees,  by  the  aid  of  his  micro- ^°'^"°'^^- 
scope,  fragments  of  partially-digested  muscular  fibre  which 
has  been  excreted  by  some  carnivorous  biped,  in  the  water 
of  the  Thames,  as  furnished  to  a  portion  of  the  inhabitants 
of  London,  he  is  perfectly  justified  in  making  the  fact 
public,  and  in  urging  the  need  for  some  amendment  in 
the  condition  of  the  metropolitan  water  supply. 

Sufficient  attention  has  not  hitherto  been  directed  to 
the  kind  of  moving  organisms  found  in  drinking  water, 

the  attention  the  forms  and  apjjcarances  of  the  various  animal  and  vege- 
table bodies  visible  in  waters,  and  of  the  extraneous  substances  with  which 
they  are  most  liable  to  be  mingled,  in  order  that  a  recognition  of  their 
difterences  may  prove  of  diagnostic  value. 


168 


MICROSCOPIC    EXAMINATION    OF   A   WATER 


and  the  lessons  taught  by  these  differences.  Mr.  Ivison 
Macadam  has  expressed  the  opinion  ^  that  the  presence  of 
the  Daphnia  pulex  and  Cyclops  quadricornis  in  a  water 
is  a  proof  of  its  purity,  because  these  water-ileas  are  not 
found  in  bad  waters,  in  which  it  appears  they  cannot  live. 
He  finds  them  in  all  our  good  impounded  waters,  such, 
for  example,  as  that  of  Edinburgh,  Eothesay,  etc. 

A  perfectly  pure  water  contains  no  suspended  matter, 
nor  any  animal  or  vegetable  life ;  but  such  is  very  rarely 
found.  The  ova  of  the  entozoa,  such  as  those  of  the  round 
and  the  thread  worms,  the  eggs  and  joints  of  the  tape- 
worm, and  small  leeches,  which  may  give  rise  to  grave 
disorders,  should  not  be  forgotten  in  making  microscopic 
examinations  of  drinking  waters.  The  endemic  hsematuria 
of  Egypt  and  the  South  of  Africa  has  been  shown  to  be 
due  to  a  htematozoon  named  bilharzia  hsematobia,  wliich 
is  disseminated  by  water  containing  its  ova.  The  germs 
of  the  parasitic  disease  named  rishta,  which  is  so 
prevalent  in  Bokhara,  are  considered  by  Jenkinson, 
Klopatoff,  Fedchenko,  and  others  to  be  diffused  through 
the  medium  of  water.  The  excellent  illustrations  in  Dr. 
Macdonald's  Gruicle  to  the  Microscojnccd  Examination 
of  Drinhing  Water,  will  be  very  helpful  to  students 
of  this  branch  of  water  analysis.  As  scientific  litera- 
ture is  possessed  of  this  valuable  guide,  I  shall  only 
add  the  following  extract  from  the  Hygienic  Clas- 
sification of  Waters  contained  in  Parkes'  Hygiene  (5  th 
edit.)  : — 


1.  Pure  and  IVhole- 

2.  UsaUe. 

3.  Suspicioits. 

4.  Impure. 

sonie. 

Same  as 

Vegetable  and  animal 

Bacteria   of    any   kind ; 

Mineral  matter ;  vege- 

No. 1. 

forms  more  or  less 

fungi ;  numerous  vege- 

table    forms     with 

pale    and    colour- 

table and  animal  forms 

endochrome ;    large 

less  ;    organic    de- 

of low  types  ;  epithelia 

animal    forms ;    no 

bris  ;      fibres      of 

or  other  animal  struc- 

organic debris. 

clothing   or    other 

tures  ;  e\-idences  of  sew- 

evidence of.  house 

age  ;  ova  of  parasites, 

refuse. 

etc. 

^  Paper  entitled  "Animal  Life  in  Fresh  Water  Reservoirs." — Aberdeen 
Meeting  of  Social  Science  Congress,  1877. 


MICROSCOPIC    EXAMINATION    OF    A    WATEE  169 

Those  who  are  conversant  with  the  use  of  the  micro- 
scope will  recognize  vegetable  tissue,  starch,  epithelial 
scales,  human  hair,  the  hair  of  cats  and  other  animals, 
wool,  bits  of  deal,  fibres  of  silk  and  linen,  cotton  filaments, 
scales  and  legs  of  insects,  and  feathers,  and  will  not  be 
puzzled  by  such  apparitions  in  the  field  of  the  microscope. 
Those  who  are  not  familiar  with  the  appearances  presented 
by  these  objects  when  magnified,  should  make  themselves 
as  soon  as  possible  acquainted  with  them  under  low  and 
high  powers.  Medical  Officers  of  Health  who  are  thus 
well  grounded  will  find  the  microscopic  contents  of  water 
an  exceedingly  interesting  and  instructive  subject  of  study. 


Label. 


CHAPTEE  X 

THE    COLLECTION    OF    SAMPLES    OF    WATER    FOR    ANALYSIS. 

Every  water  analyst  should  have  his  samples  of  water 
collected  in  strong  stoppered  glass  bottles,  supplied  by 
himself,  which  have  been  thoroughly  cleansed  with  a 
strong  acid  before  leaving  his  laboratory.  Stoneware 
bottles  should  not  be  used,  for  that  material  is  liable  to 
introduce  calcic  sulphate,  silicates,  and  common  salt 
into  the  water.  It  is  wise  to  have  an  ample  supply  of 
the  water  to  be  examined,  so  as  to  have  a  reserve  in  case 
of  such  accidents  as  the  bursting  of  a  retort,  etc.  A 
stoppered  Winchester  quart  bottle  holds  a  convenient 
amount.  By  avoiding  waste,  I  find  that  about  one  litre 
of  water  is,  as  a  general  rule,  sufficient  for  analysis,  unless 
it  is  wished  to  make  any  special  examination,  as,  for 
example,  an  estimate  of  the  amount  of  magnesia  in  a  water, 
when  a  stoppered  "  Winchester  Quart "  is  employed. 


-Sanitary  District. 


SAMPLE  FOR  ANALYSIS. 


Date  of  Collection- 
Source 


Spring,  Pump  or  Draw  Well- 
Depth  of  Well 


Nature  of  Soil  and  Subsoil- 


Distance  of  nearest  Filth  or  Drain — 
Distance  of  nearest  Cultivated  Land- 
Reason  for  Analysis 


About  twioe  the  above  size  vnll  be  found  the  most  convenient. 


COLLECTION  OF  SAMPLES  OF  WATER  FOR  ANALYSIS    1  7 1 

Before  taking  a  sample,  the  bottle  should  be  well 
rinsed  three  times  with  the  water  to  be  collected.  The 
stopper  should  be  firmly  tied  down  by  twine  or  tape,  and 
a  printed  label,  with  gummed  back,  of  the  accompanying 
description,  should  be  filled  up  and  affixed  to  the  bottle. 
It  is  a  good  plan  to  tie  down  over  the  mouth  and  stopper 
of  the  bottle  a  bit  of  guttapercha  sheeting,  to  exclude  the 
dust.  These  bottles  are  advantageously  protected  in  their 
frequent  transits  about  the  country  by  enclosing  them  in 
a  strong  box,  similar  to  that  which  is  herewith  sketched. 
Hay  and  straw,  which  are  generally  very  dusty  packing 
materials,  are  thus  avoided. 


a  a.  Elastic  pads  that  press  on  stoppers  of  bottles 

when  box  is  closed. 
b  b.  Padlock  and  fastener. 


CHAPTEE    XI 

TIME    OCCUPIED    IN    PERFORMING    AN    ANALYSIS. 

Having  estimated  the  amount  of  free  ammonia,  of  albumi- 
noid ammonia,  of  oxygen  absorbed,  of  solid  residue,  of 
chlorine,  of  nitrates  and  nitrites,  the  degree  of  hardness, 
and  having  noticed  the  appearance  of  the  solid  residue 
before,  during,  and  after  incineration,  and  having  made  a 
microscopic  examination  of  any  sediment  that  may  be 
present,  and  having  tested  the  water  for  poisonous  metals, 
and  examined  it  for  magnesia  and  sulphates,  we  are  in  a 
position  to  answer  the  question  as  to  whether  the  water 
submitted  to  us  is  good  in  every  respect  for  a  public  water 
supply.  It  will  be  urged,  with  reason,  that  such  an 
analysis  as  this,  however  desirable  it  may  be,  cannot  be 
undertaken  by  the  Medical  Officer  of  Health,  for  so  much 
time  would  be  consumed  in  water  examinations  as  to  leave 
but  little  for  other  work.  It  is  but  rarely  that  I  make 
a  complete  analysis  of  this  kind,  because  it  is  seldom 
requisite.  A  head  centre  on  all  matters  relating  to  public 
health  should  be  able  to  conduct  such  an  investigation,  in 
order  that  when  a  question  arises  as  to  which  of  several 
waters  would  be  the  best  in  every  respect  for  the  public 
water  supply  of  a  town  or  village,  he  may  be  able  to  give 
an  answer  based  on  quantitative  determinations  of  the 
several  ingredients  that  affect  the  wholesomeness  of  a 
water. 


TIME  OCCUPIED  IN  PERFORMING  AN  ANALYSIS         173 

If  the  estimation  of  the  free  and  albuminoid  ammonia, 
the  oxygen  absorbed,  and  the  chlorine,  and  the  qualitative 
test  for  nitrates,  does  not  show  conclusively  the  character 
of  a  water,  then  it  is  advisable  to  add  other  tests,  such  as 
a  quantitative  determination  of  the  nitrates  and  nitrites, 
the  incineration  of  the  solid  residue,  the  calculation  of 
the  amount  of  saline  matters,  and  the  degree  of  hardness. 

If  the  question,  "  Is  this  water  wholesome  and  good  ?"  Mode  of 
be  addressed  to  me,  I  immediately  ask  whether  any  illness  extenTof 
or  disease  has  been  attributed  to  the  employment  of  it.  analysis. 
If  there  is  a  suspicion  lest  the  water  has  interfered  with 
the  health  of  any  person  or  persons,  inquiries  are  made 
of  the  applicant  as  to  whether  there  is  any  reason  for 
suspecting   the   presence   of  organic   matter   or   metallic 
poisons,  or  whether  the  water  is  found  to  be  too  hard  for 
domestic  purposes,  or  whether  it  is  brackish  or  purgative. 
In  fact,  I  ask  what  reason  there  is  for  complaining  of  the 
water.      In  this  way  the  extent  of  the  analysis  is  limited, 
and  the  applicant  obtains  the  information  required.      In 
the  majority  of  cases  that  present  themselves,  the  question 
arises  as  to  the  amount  of  organic  matter,  whether  within 
or  beyond  the  permissible  limit. 

Now,  what  amount  of  time  is  occupied  in  answering 
this  last  question  with  absolute  certainty  ?  Thirty  minutes. 
If  it  is  needful,  as  is  often  the  case,  to  estimate  the  exact 
amount  of  organic  matter  present  in  a  water,  forty 
minutes  are  consumed.  If  a  more  complete  analysis  is 
required,  it  is  best  to  commence  by  starting  the  per- 
manganate of  potash  process  for  the  absorption  of  oxygen, 
and  whilst  it  is  proceeding  to  determine  the  amount  of 
chlorine,  and  the  quantity  of  nitrates  and  nitrites  in,  and 
the  hardness  of,  the  water,  whilst  the  distillation  is  going 
on.  The  evaporation  of  the  25  c.  c.  of  water  to  procure 
the  solid  residue,  and  the  weighing  of  the  dish  both  before 
and  after  this  operation,  of  course  proceed  simultaneously 


174        TIME  OCCUPIED  IN  PEKFORMING  AN  ANALYSIS 

with  the  distillation.  If  any  special  determination  of 
the  sulphates  or  other  mineral  ingredients  is  demanded, 
extra  time  is  required. 

Unlike  the  Frankland  and  Armstrong  process,  which 
consumes  two  and  oftener  three  days,  the  Wanklyn, 
Chapman,  and  Smith  process  is  very  rapid,  as  it  can  be 
completed  within  an  hour  by  the  most  inexperienced.  The 
Medical  Officer  of  Health  process  described  in  this  work, 
which  is  a  modification  of  the  latter,  is  generally  rather 
more  lengthy,  its  duration  being  dependent  on  the  greater 
or  less  rapidity  with  which  we  arrive  at  conclusive  evid- 
ence as  to  the  character  of  a  water. 

The  Wanklyn,  Chapman,  and  Smith  method  may  be 
expedited  by  submitting  for  examination  a  1  litre  instead 
of  a  -|-  litre  of  water,  and  multiplying  the  results  by  4 
instead  of  by  2.  This  rapid  modification  of  the  process 
is  suitable  only  for  the  Medical  Officer  of  Health  who  has 
had  some  experience  in  water  analysis,  to  whom  I  would 
recommend  it.  Messrs.  Townson  and  Mercer  have  made 
for  me  Nessler  glasses  of  a  size  adapted  for  the  examination 
of  half  the  usual  quantity  of  distillate,  namely,  2  5  c.  c. 


CHAPTEE    XII 

ENTKY    OF   ANALYSIS    IN    NOTE    AND    EECORD    BOOKS. 

The  entry  of  an  analysis  may  be  conveniently  made  in 
the  note-book  thus  : — 

Well  at  Woodhouse  Farm. 

Date  of  Collection. — April  4/77.  Source. — Well,  witli  pump, 

25  ft.  deep. 
,,         Analysis. — April  5/77.  Soil. — Sand  and  gravel. 

Distance  of  nearest  Filth. — 7  yards. 
Reason  for  Analysis. — Diarrlioea  suspected  from  use. 
For  Chlorine,  70  c.  c.  taken.      Required  of  sol.  nitrat.  silver  20  c.  c. 

.•.20  grains  per  gallon. 
For  Solids  25  c.  c.  taken. — Dish  and  Residue  .        26*251 

Dish  .  .  .        26-230 


.•.  58-8  grains  per  gallon. 

•06 
•03 
•01 

•021 
4 

•084 
700 

Free  ammonia  '02            Alb.  ammonia 
„        -007 

58-800 

55                      >5 

^^""^  •lO 

In  litre  free  ammonia  "054,  and  alb.  ammonia  ^20  milligram. 
Nitrogen  as  nitrates  and  nitrites  l^^  grain  per  gallon. 
Total  hardness  19  degrees. 

Oxygen  absorbed  in  4  hours  at  80°  F.  '2  grain  per  gallon. 
Opinion. — Water  condemned  as  unfit  for  drinking  purposes. 


176     EXTEY  OF  ANALYSIS  IN  NOTE  AND  EECORD  BOOKS 

It  is  useful  to  keep  a  record  book  of  all  analyses  for 
each  sanitary  district  alphabetically  arranged  in  parishes, 
the  pages  being  ruled  in  a  manner  similar  to  the  lines 
on  the  certificate  of  an  analysis  {vide  page  213). 

Some  make  entries  of  the  free  ammonia  and  the 
albuminoid  ammonia  in  terms  of  nitrogen,  and,  combining 
the  nitrogen  obtained  from  the  nitrates  and  nitrites,  add 
together  the  nitrogen  from  all  sources.  The  amount  of 
ammonia,  be  it  free  or  directly  derived  from  organic 
matter,  may  easily  be  represented  as  nitrogen  by  multi- 
plying by  14  and  dividing  the  result  by  17.  In  the 
foregoing  analysis  the  two  ammonias  thus  expressed  would 
be  registered  as  follows  : — 

Milligi-amrae  per  litre. 
Free  Ammonia  '054  =  Nitrogen  as  Free  Ammonia  "044 
Alb.  „  "20     =  Nitrogen  as  Alb.  „  "170 


Total  amount  of  Nitrogen  -214 


CHAPTEE    XIII 

MISTAKES    OF    WATER   ANALYSTS,    AND    HOW   TO 
AVOID    THEM 

To  avoid  errors  in  analytical  work  it  is  important  to  be 
very  cleanly,  orderly,  and  methodical.  Many  mistakes 
arise  from  a  want  of  cleanliness  and  care  in  the  collection 
of  samples.  Dirty  bottles  and  corks  should  not  be  em- 
ployed. It  is  desirable  never  to  rely  on  the  memory,  but 
to  be  business-like  and  exact  in  everything.  All  the 
details  of  an  analysis  should  be  written  in  a  book  kept 
for  the  purpose,  at  the  time  of  its  performance. 

A  water  should  always  be  examined  in  a  fresh  state  ;^"aiysis  of 
for,  by  keeping,  some   of  the  free   ammonia  leaves  the  a  fresh  and 
water,  and   other   changes   take   place.      On    April    1 3  stale  concu- 
the  water  of  an  artesian  well  yielded  free  ammonia  "36, 
and   albuminoid   ammonia    '015    milligramme   per   litre. 
On  April   16   another  portion  of  the  water,  withdrawn 
from  the  same  stoppered  bottle  as  the  first  sample,  was 
tested,  and  this  second  analysis  gave   of  free  ammonia 
•125,  and  of  albuminoid  ammonia  "015  milligramme  per 
litre.     The   water  had    lost   "235    milligramme    of   free 
ammonia  per  litre  in  three  days.     This  water  was  a  very 
pure   one.     If,  however,  it  had  contained  an  excess  of 
albuminoid  ammonia  as  well  as  of  free  ammonia,  con- 
fervoid  growths  would  have  formed  in  it  (very  rapidly 
in  warm  weather),  and  have  fed  on  the  free  ammonia. 


178 


MISTAKES   OF    WATER   ANALYSTS 


Want  of 
clieniieo- 
eeolOEfical 


With  a  decrease  of  free  ammonia  there  would  have  been 
a  decided  increase  in  the  amount  of  albuminoid  ammonia. 
"Waters  should  be  examined,  if  possible,  within  thirty-six 
hours,  in  suijimer,  after  their  removal  from  their  source, 
and  in  the  interim  they  should  be  kept  in  a  cool  dark 
place  in  stoppered  bottles. 

A  mistake  on  the  part  of  an  analyst  may  arise  from 
a  want  of  chemico- geological  knowledge.  Here  are 
knowledge,  examplcs.  An  analyst  received  a  sample  of  water 
which  did  not  prove  on  analysis  to  be  perfectly  clean, 
but,  nevertheless,  could  not  be  condemned  on  the  score 
of  an  excess  of  organic  matter.  Bearing  then  a  some- 
what indifferent  character  for  cleanliness,  he  tested  it 
for  chlorides,  and  found  a  large  excess,  which  led  him 
to  condemn  the  water.  He  was  not  acquainted  with 
the  fact  that  this  water  came  from  the  greensand,  and 
that  the  purest  waters  from  this  formation  contain  an 
excess  of  chlorine. 

A  water  from  a  deep  well  in  Essex  was  sent  to  an 
analyst  who  obtained  the  following  data  on  which  to 
form  an  opmion  : — 


Grains  per  Gallon. 

MiLLIGRAMMME  PER  LlTRE= 

Part  per  Million. 

Degrees. 

Solids. 
97-4 

Chlorine. 
37 

Free  Ammonia. 
•73 

Alb.  Ammonia. 
•04 

Hardness. 
6i 

He  saw  first  that  the  solids  were  in  excess.  The 
lar»e  amount  of  chlorine  made  him  look  with  the 
strongest  suspicion  on  the  water.  Then,  on  finding 
such  an  enormous  quantity  of  free  ammonia  he  con- 
cluded—  overlooking  the  fact  that  the  albuminoid 
ammonia  was  exceedingly  small — that  this  well  was 
polluted  with  urine.  This  water,  however,  is  quite 
pure.      He   did   not  know — (1)    That   the  water   came 


AND    HOW    TO    AVOID    THEM 


179 


from  beds  of  sand  lying  underneath  the  London  clay, 
at  a  distance  of  about  250  feet  from  the  surface;  and 
(2)  That  these  sandbeds  furnish,  in  certain  situations, 
water  of  great  purity,  which  possesses  an  excess  of 
chlorides  and  free  ammonia. 

The  following  case  occurred  some  time  since  in  one 
of  the  south-western  counties,  which  has  utterly  shaken 
the  confidence  of  the  local  public  in  their  opinion  of  their 
health   officer.     Two  waters   from   neighbouring   pumps,  a  pure  water 

1  .   1  .  .    .  .        -,    ,      and  an  im- 

which  were  open  to  some  suspicion,  were  examined  by  pure  water 
him.      The   wat^r    from   one   pump   was   pronounced   to***^®^^'"^ 
be  pure,  and  the  water  from  the  other  was  declared  to  the  same 
be   impure   and  quite   unfit   for  drinking   purposes.      It^^'^^^ 
was    ultimately    discovered    that    both    pumps    derived 
their    water    from    one    and    the    same    well.     Such    a 
lamentable  mistake  could  hardly  have  occurred  had  not 
some  utterly  fallacious  mode  of  examination  been  prac- 
tised.    In  justice,  however,  to  this  gentleman,  it  should 
be  stated   that   a   most  extraordinary  case  has  recently 
been  published  by  Sir  Charles  Cameron,  the  well-known 
health  officer  and  analyst  of  Dublin,  where  good  and  bad 
water  would  seem  to  have  been  present  in  a  deep  well 
at   the   same   time,   the   pure   lying   in   a  layer    at    the 
bottom  of  the  well,  and  the  impure  forming  a  stratum 
on  the  surface. 


Sample. 

Geains  per  Gallon. 

Qualitative. 

Part  per 

MlLLION= 

Milligramme 
PER  Litre. 

Solids. 

Chlorine. 

Nitrous  Acid. 

Nitric  Acid. 

Free 
Amm. 

Alb. 
Amm. 

No.  1 
No.  2 

29 

47-4 

2-1 
1-7 

Large  amount 
None. 

Small  amount 
Trace. 

•14 
•00 

•35 

•08 

No,  1  water  was  taken  from  the  well  by  dipping  it  out 
from  the  surface,  whilst  No.   2   was  withdrawn  from  a 


180  MISTAKES    OF    WATER    ANALYSTS 

tap,  the  pipe  of  which  descended  to  within  two  inches 
of  the  bottom  of  the  well.  Sir  Charles  Cameron  comes 
to  the  following  conclusion : — "  The  water  which  enters 
the  lower  part  of  the  well  through  its  side  and  bottom  is 
derived  from  springs,  or  at  any  rate  it  is  water  which  had 
percolated  throughout  a  considerable  quantity  of  clay, 
and  had  thereby  been  deprived  of  any  organic  matter 
which  it  might  originally  have  contained.  On  the 
other  hand,  the  drainage  of  the  surface  of  the  sur- 
rounding soil  must  have  in  part  made  its  way  into  the 
well  through  the  sides,  but  near  its  mouth.  As  this 
drainage  would  undergo  but  little  filtration,  it  would 
probably  be  contaminated  with  organic  matter,  as  sur- 
face drainage  so  generally  is."  The  writer  has  noticed  a 
similar  difference  in  quality  of  the  water  drawn  at  different 
depths  from  four  other  wells ;  in  one  case,  the  solids  per 
gallon  amounting  to  6  6 "2  3  grains  in  the  bottom  water, 
and  to  only  3  grains  in  the  top  water.  I  on  one  occasion 
analyzed  samples  of  water  taken  from  two  dijSerent 
pumps  connected  with  one  and  the  same  well  (depth 
18  feet),  both  samples  proving  exceedingly  filthy.  The 
pipe  of  the  pump  that  drew  water  from  the  bottom  of 
the  well  furnished  a  water  which  was  more  impure 
than  that  from  the  pump  that  obtained  its  supply  at  a 
higher  elevation.  The  lesson  taught  by  these  facts  is, 
that  it  behoves  the  collector  of  well  waters  for  analysis  to 
take  precautions  to  secure  samples  representing  the 
average  composition  of  the  whole  contents  of  a  well. 
Omission  to  The  mistakcs  of  water  analysts  may  arise  from  sins  of 
metafs!  omission  as  well  as  from  those  of  commission.  Two  or 
three  samples  of  a  spring  water  were  some  time  since 
submitted  by  a  Eural  Sanitary  Authority  to  a  distin- 
guished analyst  with  the  object  of  discovering  whether  or 
not  it  was  adapted  for  the  public  supply  of  a  neighbouring 
town    wliich  was    destitute  of   clean    water.       Foolscap 


AND    HOW    TO    AVOID    THEM 


181 


papers  of  formidable  appearance,  containing  details  quite 
incomprehensible  to  all  but  experts,  were  received  after  a 
delay  of  two  or  three  months,  which  contained  the 
assurance  that  the  water  was  a  very  excellent  one,  and  in 
all  respects  adapted  for  dietetic  and  all  domestic  purposes. 
No  mention,  however,  was  made  as  to  the  presence  or 
absence  of  metals.  I  maintain  that  no  one  is  justified  in 
giving  such  an  opinion  as  the  above,  unless  he  has  made 
an  examination  for  lead,  copper,  and  iron  in  a  water. 
Eesting  on  the  opinion  of  the  analyst,  expensive  water- 
works have  been  constructed,  and  the  water  has  been 
"  laid  on "  to  the  town.  The  water  contains  so  much 
iron  as  to  be  very  unpopular,  the  public  preferring  for 
drinking  purposes  the  water  of  their  polluted  surface 
wells. 

The  water  from  a  well  about  2  5  feet  in  depth  was  sent 
to  a  London  analyst,  who  pronounced  on  the  following 
data  the  opinion  that  the  water  was  "  polluted  with  sew- 
age," and  "  cannot  be  drunk  without  danger  to  health.'* 


Grains  Per  Gallon. 

Part  per  Million= 
Milligramme  per  Litre. 

Chlorine. 
3-2 

Nitrogen  as 

Nitrates  and 

Nitrites. 

•4 

Volatile 
Matters. 

5-6 

Free  Ammonia. 
•070 

Albuminoid 
Ammonia. 

•058 

The  analyst  adds,  "  The  quantity  of  chlorine  is  so 
large  as  to  be  strongly  suggestive  of  the  source  of  pol- 
lution." Here,  in  this  instance,  two  mistakes  were 
committed.  The  above  results  would  not  warrant  any 
one  in  affirming  that  the  water  was  polluted  with  sewage, 
for  it  manifestly  is  not.  They  indicate  that  the  water  is 
a  doubtful  one,  and  should  have  led  to  further  investigation. 
I  analyzed  the  water  of  this  same  well  on  two  distinct 


182 


MISTAKES    OF   WATER    ANALYSTS 


occasions,  separated  by  an  interval  of  several  montlis. 
My  figures  did  not  materially  differ  from  the  above,  except 
that  the  proportion  of  free  ammonia  was  slightly  less, 
e.g.— 


Part  per  Million  =  Milligramme  per  Litre. 

Free  Ammonia. 

Albuminoid  Ammonia. 

First  Analysis 
Second  Analysis     . 

•02 
•02 

•06 
•05 

A  microscopic  examination  of  the  sediment  showed  the 
presence  of  an  abundance  of  confervoid  filaments  on  both 
occasions.  The  amount  of  chlorine  is  rather  below  the 
average  of  the  surrounding  district,  all  the  purest  waters  of 
which  furnish  an  abundance  of  chlorides  derived  from 
sandy  strata.  It  is  perfectly  evident  that  the  water  con- 
tains vegetable  impurities  to  some  slight  extent,  and  is 
accordingly  not  of  the  best  quality.  Here  was  a  very 
serious  error  made  by  an  analyst  of  note,  who  evidently 
relied  on  the  indications  afforded  by  the  test  for  chlorine 
and  the  loss  by  incineration,  to  the  exclusion  of  that 
obtained  by  microscopic  examination,  which  is  always 
analyses  of  dcsirablc  in  doubtful  water. 

waiter  vTeid-  "^^^  apparent  disagreement  between  the  results  obtained 
ing  diflferentin  Water  analysis  by  different  analysts  was  brought  forward 
by  a  gentleman  in  the  Chemical  News  of  November  19, 
1875.  He  publishes  five  analyses  with  opinions  by  five 
chemists  of  repute,  of  the  water  from  the  same  well,  and 
appends  Ms  conclusion — 


AND    HOW    TO    A^,0ID    THEM 


183 


Deqeees. 

Grains  per  Gallon. 

Part  per 
Million  = 
Milli- 
gramme 
per  Litre. 

3i 

+2    . 

g  s 

si 

3 

02 

1 

o 

3 

o 
O 

9 

•5 

s 
< 

A. 
B. 
C. 
D. 
E. 

23-0 

31-0 
lS-6 
22-3 

7-0 

9-0 

5-8 
4-4 

16-0 

22-0 
12-8 
17-9 

27-5 
22-8 
27-0 
24-1 
26-6 

2-500 
3-500 
0-587 

1-852 

6-5 
0-5 

4-3 

0-78 
0-78 
1-25 
0-91 
]-27 

15-8 
17-0 

18-6 
16-9 

0-6 
0-7 

•01 
•00 

-10 
-01 

A.  's  verdict  is — That  the  water  is  of  gootl  quality. 

B.'s        ,,  It  is  surface  water  and  is  bad. 

C.'s        ,,  So  much  organic  matter  as  to  be  unfit  for  drinking. 

D.'s        ,,  A  perfectly  pure  water,  and  quite  fit  for  all  domestic 

purposes. 
E.  's        , ,  The  water  is  unusually  pure. 

After  such  verdicts,  surely  it  is  necessary  we  should  have  some  reforms 
in  our  practice  of  analytical  chemistry. 

The  prominence  given  in  these  analyses  to  the  mineral 
constituents  of  this  water,  to  the  exclusion,  in  three  out 
of  the  five,  of  the  more  valuable  information  as  to  the 
amount  of  filth,  is  noticeable.  The  only  analyses  on 
which  it  would  be  safe  to  offer  an  opinion,  namely,  those 
labelled  C  and  E,  show  the  water  to  be  one  of  a  variable, 
and  for  this  reason  of  a  doubtful,  or  suspicious  character. 
When  one  meets  with  such  a  water,  it  is  wise  to  make 
two  or  three  analyses  at  intervals  of  two  or  three  months, 
remembering  the  fact  that  many  wells  are  liable  to 
periodical  pollution,  dependent  on  the  height  of  the  sub- 
terranean and  ground  or  subsoil  water,  and  other  causes. 
I  have  heard  of  as  many  as  nine  samples  of  an  intermittent 
public  water  supply  having  been  taken  at  different  times 
of  the  day  (24  hours)  by  an  analyst  who  felt  convinced 


184  MISTAKES    OF   WATER    ANALYSTS 

that  some  occasional  pollution  did  occur.  Eight  samples 
proved  on  analysis  to  be  pure.  On  making  the  ninth 
analysis  he  obtained  proof  of  considerable  organic  con- 
tamination of  the  water.  There  is  no  evidence  afforded 
that  the  samples  of  water,  the  analyses  of  which  form  the 
foregoing  table,  were  all  taken  at  the  same  time  in  per- 
fectly clean  vessels,  as  was  very  properly  pointed  out  by 
the  public  analyst  of  Cornwall 


CHAPTEE    XIV 

USEFUL    MEMOEANDA     FOR    MEDICAL     OFFICERS     OF    HEALTH 
WHEN  PERFORMING   WATER   ANALYSIS 

1.  Thoroughly  wipe  away  all  dust  from  the  mouth  of  Memoranda, 
the  sample   bottle  and  stopper  with  a  clean  glass-cloth 
before  commencing  an  analysis. 

2.  The  hole  at  the  upper  extremity  of  the  standard 
ammonia  solution  burette,  for  admitting  air  when  the 
liquid  is  drawn  off  by  the  tap,  should  be  closed  by  turning 
around  the  glass  stopper,  before  leaving  the  laboratory  for 
the  day,  otherwise  evaporation  will  take  place,  and  the 
remaining  standard  solution  will  become  stronger  than  it 
should  be  when  next  employed.  For  the  same  reason  it 
is  undesirable  to  place  more  standard  ammonia  solution 
in  the  burette  at  a  time  than  will  be  probably  required. 
If,  at  the  conclusion  of  one's  work  in  the  laboratory,  a 
little  solution  only  remains,  it  is  as  well  to  throw  it  away, 
and  replace  it  by  fresh  from  the  stock  bottle  when  next 
wanted. 

3.  On  adding  the  caustic  potash  and  permanganate  of 
potash  solution  in  the  estimation  of  the  albuminoid  am- 
monia, it  will  be  often  noticed  that  on  reapplying  heat  the 
steam  that  first  passes  off  is  not  condensed,  but  escapes 
as  such  into  the  ISTessler  glass.  It  is  wise  to  hold  up  the 
Nessler  glass  so  that  the  steam  issuing  from  the  condenser 
tube  may  impinge  on  its  cold  base,  and  be  thus  condensed. 


186      MEMOEANDA  FOR  MEDICAL  OFFICEES  OF  HEALTH 

4.  Sample  bottles  are  exceedingly  apt  to  fur,  especially 
in  warm  weather,  if  waters  are  long  kept  in  them,  and 
difficulty  is  often  experienced  in  cleansing  them.  "Waters 
containing  much  free  ammonia  are  especially  liable  to  the 
growth  of  confervse.  It  is  desirable  to  wash  out  a  sample 
bottle  directly  an  analysis  is  completed.  Bottles  that  have 
the  slightest  fur  about  them  should  be  cleaned  with  strong 
impure  hydrochloric  acid  and  fragments  of  filter-paper. 
If  this  acid  in  a  cold  state  fails  to  remove  the  fur,  boiling 
acid  must  be  employed.  A  most  thorough  washing  with 
water  is  of  course  indispensable  after  the  use  of  the  acid. 

5.  Look  narrowly  for  insect  life  in  each  sample  of 
water  submitted  for  examination.  If  a  well  water  con- 
tains animal  life  of  such  a  size  as  to  be  perceptible  to  the 
unaided  eye,  it  is  almost  useless  to  analyze  the  water  for 
organic  matter,  of  which  there  is  sure  to  be  an  excess. 
Animals  will  not  exist  in  a  fluid  that  does  not  possess 
organic  matter  on  which  they  can  feed.  The  presence  of 
a  distinct  brown  tinge  in  the  water  is  often  confirmatory 
in  such  a  case  of  the  presence  of  filth.  Sometimes  speci- 
mens of  entomostraca  may  be  seen  along  the  edges  of  lakes 
and  large  reservoirs  that  supply  towns  with  water.  In 
such  cases  the  volumes  of  water  with  which  they  are  as- 
sociated are  so  enormous  that  an  analysis  does  not  show 
any  excess  of  organic  matter  in  consequence  of  their 
presence. 

6.  Some  of  the  ammonia  found  in  rain  water  that 
falls  near  dwellings  is  derived  from  the  soot,  for  ammonia 
is  a  product  of  combustion. 

7.  In  the  estimation  of  the  solid  residue  it  is  advisable 
to  examine  the  under  surface  of  the  platinum  dish,  after 
the  evaporation  to  dryness,  before  the  dish  is  weighed,  and 
to  carefully  remove  any  saline  matter  derived  from  the 
water  of  the  water  bath.  It  is  always  best  to  employ 
distilled  water  in  the  bath. 


WHEN  PERFOEMING  WATER  ANALYSIS  187 

8.  The  greater  or  less  rapidity  with  which  the  solid 
residue  increases  in  weight  during  weighing  is  an  indica- 
tion as  to  the  amount  of  the  deliquescent  salts  common  to 
water  residues,  such  as  the  chlorides  of  calcium  and  mag- 
nesium, the  nitrite  of  potash,  etc.,  which  are  present. 

9.  After  the  analysis  of  a  very  impure  water,  it  is 
wise  to  distil  a  little  distilled  water  through  the  retort  and 
condenser  tube,  in  order  to  be  sure  that  the  apparatus  is 
perfectly  free  from  any  traces  of  ammonia. 

10.  Loosen  the  connection  between  the  retort  and  the 
adapter  or  condenser  tube  after  an  analysis,  to  prevent  a 
fracture,  which  will  sometimes  occur  on  cooling  if  this 
precaution  is  not  taken. 

11.  The  health  officer  should  be  prepared  to  deal  with 
frauds  with  which  the  public  occasionally  amuses  itself. 
Analysts  have  received,  for  example,  samples  of  pure 
water  into  which  a  little  soup  or  beef  tea  or  mutton  broth 
has  been  introduced ;  also  samples  of  distilled  water  as 
obtained  from  druggists,  and  samples  of  rain  water. 

12.  Nessler  glasses  are  sometimes  made  of  such  thick 
glass,  especially  at  their  bases,  as  to  give  a  distinct  tinge 
of  colour  to  colourless  water.  It  is  accordingly  wise  to 
select  colourless  and  thin  glasses,  which  should  be  all  of 
exactly  the  same  diameter. 

13.  Time  is  economized  and  accuracy  is  promoted  if 
a  separate  graduated  pipette  be  kept  for  each  standard 
solution.  A  pipette  should  be  filled  by  suction  with  the 
standard  solution  to  which  it  is  assigned,  so  as  to  moisten 
its  interior  before  the  solution  is  employed. 


CHAPTEE   XV 

FOEMATION     OF    OPINIOX   AXD    PEEPAEATION    OF    EEPOET    AS 
TO    SAMPLE    OF    WATEE    SUBMITTED    TO    ANALYSIS 

A  FELLOW  of  the  Chemical  Society  writes  thus  i^ —  "  The 
facts  in  connection  with  water  analysis  are  not  a  subject 
of  dispute,  but  the  deductions  to  be  derived  from  the  facts ; 
and  here  we  enter  a  region  which  is  altogether  outside 
the  province  of  a  chemist  pure  and  simple,  his  usurpation 
to  the  contrary  notwithstanding,  and  the  question  becomes 
one  rather  for  the  medical  expert." 

Mr.  Simon  rightly  insists  upon  a  high  standard  of 
purity  for  drinking  water.  In  his  second  annual  report 
to  the  city  of  London,  he  observes  that  "we  cannot  expect 
to  find  the  effect  of  impure  water  always  sudden  and 
violent.  The  results  of  the  continued  imbibition  of  pol- 
luted water  are  indeed  often  gradual,  and  may  elude 
ordinary  observation,  yet  be  not  the  less  real  and  appreci- 
able by  close  inquiry.  In  fact,  it  is  only  when  striking 
and  violent  effects  are  produced  that  public  attention  is 
arrested ;  the  minor  and  more  insidious,  but  not  less 
certain  evils,  are  borne  with  the  indifference  and  apathy 
of  custom."  Although  no  sickness  may  be  produced 
during  the  life  of  a  man  by  the  habitual  use  of  an  impure 
water,  yet  there  can  be  no  question  but  that  impure 
water,  like  impure  air,  affects  the  physique  of  individuals, 

1  "  PotaLle  "Water,"  by  Charles  Ekin. 


OPINION    AS    TO    SAMPLE    OF    WATER  189 

and  tends  to  the  degeneration  of  a  race.  Nearly  every 
water  contains  some  organic  matter  which,  however,  in 
exceedingly  minute  quantities  is  harmless,  so  far  as  our 
knowledge  extends.  Wlien  its  amount  in  a  water  exceeds 
a  certain  limit,  it  is  unwise  to  drink  the  water.  If  it  is 
present  in  still  larger  quantities,  the  drinking  of  such 
water  is  attended  with  risk,  or  even  with  danger.  Some  Delusions  of 
may  triumphantly  observe  that  they  have  been  endanger- ^^^p*^^"*^' 
ing  their  health  during  a  great  many  years,  and  are  not, 
to  their  own  knowledge,  at  all  the  worse  for  the  filth  that 
they  have  taken  with  their  water.  They  conclude,  there- 
fore, that  impure  water,  like  tea  against  which  the  old 
woman  of  ninety  was  warned  as  a  stealthy  poison,  must 
be  exceedingly  slow  in  its  action.  When  will  the 
public  learn  that  what  is  apparently  harmless  to  one 
is  poison  to  another ;  that  some  constitutions  are  sus- 
ceptible to  a  disease  to  which  others  are  quite  insus- 
ceptible ;^  that  the  susceptibility,  when  it  exists,  may 
only  manifest  itself  at  certain  ages  or  periods  in  a  life,  or 
even  times  of  the  year ;  that  a  person  may  at  one  time 
be  susceptible  to  a  disease,  and  at  another  time  be 
insusceptible  ?  Wliat  a  mistake  then  is  it  for  a  man  to 
argue  that,  because  he  has  drunk  filthy  pond  water  all 
his  life,  and  fancies  that  he  has  never  suffered  thereby, 
therefore  such  water  is  not  injurious  to  health,  when  we 
physicians  can  prove  that  it  will  often  produce  fatal 
diarrhoea.  Because  pond  water  does  not  ahoays  cause 
such  disastrous  results  to  all,  such  a  man  will  argue  that 
it  can  never  do  so  to  any.  We  know  much,  but  we  have 
yet  much  to  learn  as  to  the  influence  of  impure  water  on 
the  health  of  those  in  whom  it  does  not  produce  disease. 

^  Ample  proof  of  the  accuracy  of  this  statement  is  obtainable.  "Wit- 
ness, for  example,  the  distressing  symptoms  produced  in  some  people  by 
the  inhalation  of  the  pollen  of  certain  grasses,  which  form  a  complaint 
known  by  the  name  of  hay  fever,  whilst  the  majority  of  persons  are  un- 
affected by  the  same. 


190       OPINION    AND    PEEPARATION    OF    EEPOET   AS    TO 

The  study  of  this  sulDJect  forms  part  of  the  greater  one, 
as  to  the  modus  o'pcrandi  of  various  climates  on  the  health 
and  character  of  men  and  animals. 

The  question  as  to  the  suitability  of  peaty  waters  for 
the  supply  of  individuals  and  communities  often  presents 
itself.  The  objections  to  such  waters  are  twofold.  (1) 
They  are  apt  to  produce  diarrhoea  in  those  unaccustomed 
to  their  use.  Experiments  made  under  the  superintend- 
ence of  Prof.  Mallet  showed  that  peaty  waters,  and 
waters  containing  an  infusion  of  dead  forest  leaves,  were 
distinctly  injurious  to  rabbits.  (2)  Peaty  waters  are 
generally  unpalatable  and  insufficiently  aerated.  Al- 
though they  are  soft  and  free  from  nitrogen  as  nitrates 
and  nitrites,  they  are  not  properly  oxygenated.  They 
are  accordingly  unsuitable  as  public  supplies  where  a 
non-peaty  water  can  be  procured. 

The  French  chemists  consider  that  all  potable  waters 

should  contain  33  per  cent  of  dissolved  oxygen. 

Should  pond       The  miuds  of  health  of&cers  have  often  been  exercised 

condemned  as  to  the  propriety  of  condemning  pond  water  for  domestic 

as  unfit  for  ^gg^     j£  ^^  watcr  bc  storcd  in  clean  vessels  like  the 

drinking 

purposes?  drinking  ponds  in  the  chalk  districts,  and  as  the  "mist 
ponds,"  situated  in  high  uncultivated  hills  in  the  north  of 
England,  which  are  said  never  to  become  dry,  being  re- 
plenished by  the  fogs  which  they  condense ;  or  if  a  pond 
is  lined  with  cement,  and  so  protected  as  to  prevent  the 
entrance  of  ditch  water: — water  will  probably  be  furnished 
that  is  admissible.  It  will  not,  in  fact,  differ  from  the 
water  of  a  lake  or  reservoir.  Knowing,  as  we  all  do, 
that  pond  water  as  usually  met  with  (1)  is  apt  to  create 

Its  injurious  diarrhoea  in  summer;  (2)  that  those  who  drink  it  are 
generally  troubled  with  intestinal  worms ;  (3)  that  these 
ponds  are  usually  fed  by  ditches  that  drain  fields  which 
are  often  manured  by  town  filth ;  and  (4)  that  there  is 
a    strong    suspicion    of    the    existence   of   a    connection 


effects. 


SAMPLE    OF   WATER    SUBMITTED    TO    ANALYSIS       191 

between  tlie  emplojaiient  of  pond  water  and  the  pre- 
valence of  malarial  diseases  :^ — we  cannot,  in  the  interests 
of  the  public  health,  approve  of  its  adoption  for  drinking 
purposes.  Families  provided  with  this  objectionable 
supply  generally  either  strain  the  water  through  muslin, 
or  boil  the  water,  or  pass  it  through  a  filter,  or,  if  very 
turbid,  a  pinch  of  alum  is  added  to  clarify  it.  The 
father  of  a  family  drinks  little  else  than  beer,  and  the 
mother's  beverage  is  tea.  In  summer  and  autumn,  when 
there  is  a  tendency  to  intestinal  disorders,  I  have  known 
entire  families  in  rural  districts,  who  have  not  taken  the 
trouble  thus  to  lessen  the  evil,  thoroughly  prostrate  from 
severe  diarrhoea ;  and  if  the  pond  water  has  been  fouled 
by  the  excreta  of  cattle,  a  form  of  continued  fever,  re- 
sembling closely  enteric  fever,  has  been  induced.  If  the 
excreta  are  of  human  origin,  the  danger  is,  of  course,  the 
greater.  This  summer  or  autumn  diarrhoea  is  doubtless 
at  times  produced  by  direct  mechanical  irritation,  and  at 
others  by  the  absorption  into  the  blood  of  septic  matters. 
We  have  most  of  us  in  our  memories  instances  of  persons 
who  have  employed  no  other  water  than  that  from  a 
pond  in  summer  full  of  insect  life,  for  all  domestic 
purposes,  and  whose  health  has  not,  to  the  eye  of  a  casual 
observer,  suffered.  I  have  known  a  man  who  died  at  the 
ripe  age  of  between  80  and  90  years,  and  who  boasted 
that  he  had  drunk  nothing  but  pond  water  for  between 
30  and  40  years.  I  have  also  known  a  man  who 
reached  the  age  of  90,  and  who  consistently  led  for  about 
50  years  a  most  drunken  and  dissolute  life. 

Thames  water  collected  below  London  Bridge,  if  allowed 
to  stand  in  an  open  vessel  for  a  few  days  in  warm  weather, 

^  Case  of  an  outbreak  of  ague  at  Tilbury  Fort  in  1872.  Case  of  an 
outbreak  of  malarious  disease  recorded  by  Boudin  amongst  certain  soldiers 
in  one  ship  supplied  with  marsh  water  during  their  voyage  from  Algiers 
to  Marseilles,  whilst  their  comrades  in  another  ship  which  was  furnished 
with  good  water  were  all  well. 


192       OPIXIOX    AND    PEEPARATIOX    OF    EEPOET    AS    TO 

acquires  a  very  offensive  odour  arising  from  the  decom- 
Thames  position  of  the  animal  and  vegetable  matter.  This  water 
water.  ^.^^  formerly  valued  by  sailors,  and  stored  on  board  ship 
in  wooden  casks.  When  drunk,  it  was  the  custom  to 
wipe  away  the  solid  matters  that  collected  on  the  lips, 
after  taking  a  draught,  with  the  back  of  the  hand. 
During  the  first  week  or  fortnight  of  its  storage  in  the 
hold,  ship  captains  found  that  the  water  underwent  a 
change  described  as  a  kind  of  fermentation,  evohing  a 
quantity  of  gas  possessing  a  most  offensive  odour  and 
depositing  a  copious  brown  sediment.  The  gases  produced 
in  the  wooden  casks  were  said  to  be  slightly  luminous  in 
the  dark  and  to  be  explosive.  The  coagulation  of  the 
albuminous  constituents  of  the  water  by  the  tannic  acid  of 
the  oaken  casks  probably  occurred.  The  water  gradually 
ceased  to  smell  offensively,  became  bright  and  sparkling, 
and  was  said  to  keep  fresh  and  sweet  for  an  indefinite 
length  of  time,  ha\Tiig  lost  the  whole  of  its  putrescent  im- 
purities. Pond  water  has  been  known  to  undergo  a  similar 
change  on  board  ships.  In  our  war  vessels,  etc.,  iron  tanks 
are  used  instead  of  casks  for  storing.  It  is  said  that  in  u-on 
tanks  Thames  water  evolves  no  offensive  gases,  but  becomes 
pure  much  quicker  than  when  stored  in  wood,  and  deposits 
a  more  copious  brown  sediment  which  turns  red  on  ex- 
posure to  air.  Iron  possesses  a  wonderful  power  of 
causing  the  precipitation  of  the  organic  matter  and  some 
of  the  saline  constituents  of  a  water. 
Information       j^  j^^s    been  Urged,  as   a    serious    objection    to    the 

as  to  source,  _^  in-i 

surround-     Wanklyu,  Chapman,  and   bmith  process,  by  those  who 
mgs,  etc.,    -bejjeye  i^  the  Frankland  and  Armstroncr  process,  that  an 

of  water,  a  o  x  ' 

sample  of    opuiion  of  the   smallest   value   cannot   be   formed  of  a 
te^'aMiyzTd.  ^^tcr  examined  by  the  former  process  without  the  fullest 
information  as  to  soil,  situation  of  source  of  water,  dis- 
tance of  possible  centres  of  pollution  depth  of  well,  etc. 
Let  any  one  read  the  printed  instructions  of  Dr.  Frank- 


SAMPLE    OF   WATER    SUBMITTED    TO    AXALYSI3       193 

land/  sent  out  by  Mm  to  those  who  collect  samples  of 
water  to  be  analyzed  in  liis  laboratory,  and  it  will  be 
seen  that  be  requires  a  similar  amount  of  information  for 
his  own  guidance.  The  reason  of  this  is  ob^ious.  Every 
system  of  water  analysis  at  present  known  has  its  weak 
points,  some  possessing  more  than  others ;  accordingly, 
the  best  methods  hare  to  be  fenced  around  with  certain 
protections  against  error. 

It  is  a  golden  rule  in  water  analysis  never  to  give  anGoMenmies 
opinion  unless  the  analyst  knows  (1)  the  nature  of  the^^J^^^" 
source  of  a  water — whether  it  comes  from  a  spring,  or 
well,  or  Tirev,  or  rain  reservou^  etc. ;  (2)  the  depth  of  the 
well,  if  it  is  withdrawn  from  one ;  (3)  the  geology  of  the 
district  from  which  it  is  derived,  together  with  the  char- 
acter of  the  soil  and  subsoil ;  (4)  the  distance  from  the 
source  of  the  water  of  the  nearest  filth  or  drain.  Another 
golden  rule  is  never  to  give  an  opinion  as  to  the  character 
of  a  water  from  an  estimation  of  one  ingredient  only  in 
the  water.  A  very  serious  mistake  has  often  been  made 
by  those  who  practise  the  ammonia  process  of  water 
analysis,  which  has  thrown  great  discredit  on  the  chemistry 
of  the  subject.  This  mistake  has  been  to  deliver  an 
opinion  on  the  quality  of  a  water  which  has  been  soldi/ 
formed  from  a  determination  of  the  amount  of  albuminoid 
ammonia  contained  in  it.  The  practice  of  tabulating  side 
by  side  with  the  total  amount  of  albuminoid  ammonia  in  a 
water,  the  fact  of  the  appearance  or  otherwise  of  any  pre- 

^  "At  the  time  the  samples  are  forwarded  for  analysis,  give  the  fol- 
lowing particulars  : — (a)  From  what  source — Wells,  rivers,  or  streams  ?  if 
from  wells,  {h)  describe  the  soil  and  subsoil,  and  also  the  water-bearing 
stratum  into  which  the  well  is  sunk ;  (c)  the  diameter  and  depth  of  well  ; 
(rf)  the  distance  of  the  well  from  either  cesspools  or  di-ains  ;  if  from  rivers 
and  sti-eams,  (c)  the  distance  from  the  source  to  the  point  at  which  sample 
is  collected  ;  (/)  whether  sewage  or  other  animal  polluting  matter  is  known 
to  gain  access  to  river  or  stream  above  the  point  of  collection  ;  if  from 
springs,  [g)  describe  the  stratum  from  which  the  spring  issues  ;  {h)  state 
whether  the  sample  is  taken  direct  from  spring  or  otherwise,"  etc. 

0 


194       OPINIOX    AND    PEEPAEATION    OF    REPORT    AS    TO 

ventable  disease  amongst  those  who  had  been  in  the  habit 
of  employing  it,  an  example  of  which  may  be  seen  in  Table 
VII.  of  Dr.  de  Chaumont's  Lectures  on  State  Medicine,  is 
apt  to  be  misleading.  The  arrangement  of  a  table,  in 
which  the  valuation  or  opinion  of  the  analyst  as  to  each 
water  (as  formed  from  the  observance  of  certain  rules  for 
guidance)  is  placed  in  juxtaposition  to  the  name  of  the 
disease,  if  any,  apparently  produced  by  it,  would  be  ex- 
ceedingly interesting  and  of  great  practical  value. 

Sanitary  authorities  will  sometimes  present  to  a 
Medical  Officer  of  Health  a  sample  of  very  dirty  water, 
which  is  reported  to  come  from  a  well,  and  will  ask  him 
whether,  if  the  weU  is  cleaned  out,  the  water  will  be  good. 
This  question  can  only  be  partially  answered  by  an 
analysis.  The  hardness  of  the  water  can  be  rouglily 
ascertained,  and  the  presence  or  absence  of  objectionable 
ingTcdients,  such  as  purgative  salts,  metals,  etc.,  can  be 
determined.  A  muddy  water  has  often  been  sent  to  me 
derived  from  a  new  well  recently  dug,  with  a  wish  that  I 
should  ascertain  whether  there  is  any  excess  of  organic 
matter  in  it.  Such  an  inquiry  is  equivalent  to  the 
following  : — "  I  have  placed  filth  (for  mud  contains  organic 
matter)  in  the  water.  \ATien  I  cease  to  introduce  filth. 
Turbid  will  the  Water  be  free  from  any  ?"  Here  are  examples 
waters  from  gf  turbid  waters  from  new  wells  which  have  become  pure 

recently  dug  . 

wells.         after  repeated  removal  of  their  contents  by  pumpmg  : — 


SAMPLE    OF    WATER    SUBMITTED    TO    ANALYSIS        195 


Grains  per  Gallon. 

Part  per 

Million  = 

Milligramme 

PER  Litre. 

Degrees. 

to 

o 

111 

c3 

g'i 

2  • 

c 
"S 

Well  (25  ft.)  in  gravel 
g|  .   C  Sept.  16  (fl.) . 
E|  y  Sept.  25  {b)  . 
I.S  ""  (  Oct.    15  (c)  . 

51 

21 

7 

2-1 

2 

None 

I  ! 
)) 

•01 
•56 
•02 

•02 

■175 
•24 
■09 
•04 

13 

The  estimation  of  the  nitrates  and  nitrites  is  valuable 
in  such  cases  as  the  above,  for  it  often  gives  information 
respecting  the  surroundings  of  the  well.  The  Medical 
Officer  of  Health  can  frequently  clear  up  any  obscurity 
that  may  exist,  by  himself  visiting  the  well  and  noting 
its  situation,  etc. 

A.  Summary  of  Data  on  which  to  base  an  Opinion. 


1.  Odour. 

2.  Colour  through  tuhe. 

3.  Free  Animo7iia — Its  amount.  ^ 

4.  Albuminoid  Ammonia — Its  amount  I     Smell  of 

and  manner  of  distilling      j   distillates? 
over,  J 

5.  Oxygen  ahsorled  in  4  hours  at  80°  F. — Its  amount. 

6.  Nitrogen   as   Nitrates   and   Nitrites. — Its    amount. 

Nitrates  or  Nitrites  ? 

7.  Solid     Residue — Its     amount.       Behaviour     with 

Hydrochloric  Acid,  Appearance  Be- 
fore, During,  and  After  incineration  at 
a  dull  red  heat.  Amount  of  Volatile 
matters. 


Summary  of 
data  on 
which  to 
form  a  judg- 
ment. 


196       OPIXION    AND    PREPAEATIOX    OF    EEPOET    AS    TO 

8.  Chlorine — Its  amount. 

9.  Hardness — Total,  Temporary,  Permanent. 

10.  Microscopic  Ejcmnination   of  Sediment — Xature    of 

objects  observed, 

11.  Biological  Examination. 

12.  Metcds.  I  oJpper  \  ^^^^^^^^^  °^'  non-existence.     If 

J     J  (  present,  tlie  amount. 

13.  Mineral         ^  ,^  •     n  i        n  n  -r^ 

,^  (  Magnesia,  Salts  oi  j  Present   or    ab- 

, .   , .      , ,  <  Sulphates  >  sent.  If  present, 

obiectionaoie  I  -^^^       ^    .  I    -i 

.^  .  f  Phosphates.  )  the  amount. 

%j  m  excess.  ^  ■' 

In  the  great  majority  of  cases  that  present  themselves 
to  the  Medical  Officer  of  Health  a  complete  analysis  of  this 
sort  is  not  wanted.  In  nine  cases  out  of  ten  the  ques- 
tion to  which  an  answer  is  required  is,  as  to  whether  a 
water  is  or  is  not  polluted  with  filth.  To  reply  to  this 
query  it  is  simply  necessary  to  ascertain  the  amount  of 
free  and  of  albuminoid  ammonia.  If  the  applicant  wishes 
to  know  if  the  filth  is  of  animal  origin  or  decayed  vege- 
table matter,  we  must  estimate  the  quantity  of  chlorine 
and  nitrogen  in  the  form  of  nitrates  and  nitrites.  If  the 
interrogation  is  submitted  to  us  as  to  whether  or  not  a 
water  devoid  of  filth  is  in  other  respects  wholesome,  a 
calculation  of  the  amount  of  solid  residue,  of  the  hardness, 
etc.,  is  needful. 

B.  Valuation  Tables  and  Disteict  Standaeds. 

It  would  be  a  great  convenience  to  the  analyst  if  he 

were  able  to  appraise  each  determination  at  its  true  value 

Mr.wigner'sin  a  definite  manner,  which  can  be  represented  in  figures. 

tabie.*^°^    The  late  Mr.  Wigner  with  this  object  in  view,  constructed 


SAMPLE    OF  WATER    SUBMITTED    TO    ANALYSIS        197 


a  table  ^  which  gives  the  values  in  degrees  of  impurity  of 
the  several  data  on  which  an  o]3inion  is  to  be  based. 


Appearance  in  two-foot  tube. 
C.  Blue     . 
C.   Pale  yelloAv  . 
C.  Green 
C.  Dark  j'ellow . 
C.  Dark  oreen   . 


Suspended  matter  to  he  added  to  the  valuation  of  ajjpearance. 


For  traces 
,,    heavy  traces 
,,    turbidity 


S'inell  when  heated  to  100°  F. 
Vegetable  matter         ....  1 

Strong  peaty       .....  2 

Offensive,  of  animal  matter  ...  4 

Clilorine  in  Chlorides  ....    '50  gr,  per  gall.  = 

Phosphoric  acid  as  phosphates,  traces  =  2.  h  traces  =  4.  v  h  traces  = 
Nitrogen  in  nitrates  .  .  .  .  .  "100  gr.  per  gaU.  = 

Ammonia  ......  '005  ,,  = 

Alb.  ammonia  ......  "001  ,,  = 

Oxygen  absorbed  in  15  min.  at  80°  F.  .  -002  gr.  per  gall.  = 

„  „  4  hours      „         .  .  "010  ,,         ;  = 

Hardness  before  and  after  boiling  added  together  each  5°  = 

Total  solid  matter     .....      5  grs.  per  gall.  = 

Heavy  metals   .......       s    traces  = 


Microscopical  Results. 

Vegetable  debris  in  small  quantity       .... 

„  ,,         large  „         .  .  .  . 

Diatoms  and  bacteria  in  small    „  .  .  .  . 

large    „  .  .  .  . 

Hair  and  animal  debris  (according  to  quantity  observed) 


=  12 


6 

.      12 
10  to  20 


Rules. 


A  valuation  at  or  below  15. 
,,      60. 


=  Exceptional  purity. 
=  First  class  Avater. 
=  Second 


Analyst,  July  1881. 


198       OPINION    AND    PKEPAKATION    OF    REPORT    AS    TO 

The  metropolitan  companies  furnish  waters  that  show 
a  value  on  this  scale  varying  between  20  and  40. 

The  foregoing  table  possesses  three  or  four  grave 
defects. 

1.  Some  of  the  purest  waters  contain  a  large  excess 
of  free  ammonia,  and  yet  each  '005  gr.  per  gall,  is 
valued  at  1. 

2.  Good  artesian  well  waters  often  contain  a  large 
quantity  of  chlorine,  and  yet  each  "5  gr.  per  gall,  is 
valued  at  1. 

3.  Waters  which  cannot  be  condemned  on  account  of 
the  presence  of  peat  absorb  a  large  amount  of  oxygen,  and 
yet  each  '01  is  valued  at  1. 

4.  Artesian  waters  organically  pure,  although  not  of 
the  best  quality,  contain  large  amounts  of  solids,  and  yet 
every  5  grs.  per  gall,  are  valued  at  1. 

Dr.  Muter's        j)x.  Mutcr  has  suggcstcd  ^  the  following  amendment  of 

amended  ,  i       j  •         j_    i  i 

valuation    tlic  abovc  vaiuation  table. 

table.  Gr.        Valuation 

per  gall.      number. 

Ammonia    .....  each  '0015  =  1 

Alb.  ammonia                 ...  „      -0007  =  1 

Oxygen  consumed  in  1 5  min.          .  „     -0040  =  1 

„                 „              4  hrs.           .  „      -0100  =  1 

He  writes,  "  When  any  number  exceeds  1 0,  then  all 
over  1 0  is  to  be  doubled  and  added  to  the  original  number, 
and  the  total  valuation  is  to  be  divided  by  100  and 
noted  as  comparative  degree  of  organic  impurity.'  Then 
S2cp2Josmg  no  other  consideration  intervenes  to  modify  the 
analyst's  opinion  of  the  sample,  I  propose  that  the  following 
limits  should  be  observed : — 

First  class  water   ....         np  to  '25  degree. 
Second  „        „      .  .  .  .  np  to  -40  degree. 

Undrinkable  „       .  .  .  .  over  -40  degree." 

^  Analyst,  June  1883. 


SAMPLE    OF    WATER    SUBMITTED    TO    ANALYSIS        199 

The  divergence  in  views  as  to  the  relative  values 
might  be  minimized  by  excluding  from  the  late  Mr. 
Wigner's  valuation  table  any  values  for  microscopical 
results,  leaving  them  to  individual  opinion/  and  by 
omitting  and  diminishing  the  values  of  free  ammonia, 
chlorine,  oxygen  absorbed,  and  total  solids  under  certain 
conditions. 

Some   adjustment    of   the   following   kind   might    be  Author's 
thought  feasible.  ^'^ig^es  ions. 

Free,  ammonia  if  in  large  excess  is  not  to  be  valued, 
unless  accompanied  by  an  excess  of  albuminoid  ammonia. 

Oxygen  absorbed  in  4  Jioicrs  at  80°  F.,  if  in  large 
excess  is  not  to  be  valued  beyond  the  value  of  the  average 
of  a  water  of  medium  purity,  if  an  upland  surface  water, 
or  water  other  than  upland  surface  water,  as  the  case  may 
be  {vide  page  33),  unless  accompanied  by  an  excess  of 
nitrogen  as  nitrates  and  nitrites. 

Chlorine  if  in  large  excess  is  not  to  be  valued  unless 
accompanied  by  an  excess  of  ammonia  and  albuminoid 
ammonia,  nitrogen  as  nitrates  and  nitrites,  and  oxygen 
absorbed  in  4  hours  at  80°  F. 

Total  Solids  if  in  large  excess,  as  e.g.  in  artesian  wells, 
are  to  be  valued  at  10  grains  =1,  unless  there  is  an 
excess  of  albuminoid  ammonia,  when  the  late  Mr. 
Wigner's  value,  5  grains  =1,  may  be  employed.  If  some 
such  qualified  valuation  were  adopted,  the  total  values  in 

^  My  own  views  as  to  the  relative  values  of  the  several  microscopic 
objects  with  which  one  is  familiar,  would  lead  me  to  place  them  in  the 
following  order,  commencing  with  those  of  least  and  concluding  with  those 
of  most  imjjoitance  :— 

1.  Vegetable  matters. 

2.  Diatoms  and  desmids  {vide  p.  165  footnote). 

3.  Animal  life. 

4.  Animal  debris  such  as  epithelial  scales,  human  hairs,  partiall}'  digested 
articles  of  food,  fungi,  etc. 

5.  Bacteria  or  bacilli  so  numei'ous  as  to  be  seen  in  each  field  of  the 
microsco}ie. 


200      OPINION    AND    PEEPAEATION    OF    EEPOET    AS    TO 

the  rules  as  to  the  classij&cation  of  waters  in  accordance  with 
their  valuation  would  have  to  be  altered.  Any  valua- 
tion table  that  could  be  framed  would  be  necessarily  a 
mere  rough  guide,  in  which  every  one  might  find  some- 
thing to  carp  at.  The  history  of  a  water,  its  surroundings, 
and  the  knowledge  of  the  geological  formation  from  which 
it  is  obtained,  must  be  allowed  to  have  a  certain  bearing 
on  the  judgment  of  the  analyst. 
District  The   autlior   is    disposed   to    agree   with   the   opinion 

standards,  gxpresscd  by  Dr.  Dupre  and  Mr.  Hehner,-^  that  the 
establishment  of  "  district  standards  "  is  preferable  to  the 
adoption  of  a  general  standard.  They  consider  that  the 
fitness  of  any  given  sample  of  water  for  drinking  purposes 
is  best  judged  "  by  its  conformity  to,  or  divergence  from, 
the  general  character  of  the  waters  of  the  district  from 
which  it  comes  (or  the  geological  formation  from  which  it 
springs),  which  from  their  surroundings  may  fairly  be 
taken  as  unpolluted." 

The  knowledge  of  the  composition  of  the  good  well 
water  of  the  locality  from  which  the  sample  comes,  which 
a  Medical  Officer  of  Health  imperceptibly  acquires  after  a 
time,  often  aids  him  in  determining  the  nature  of  the 
water  brought  to  him  for  analysis. 

C.  Diagnosis  and  Formation  of  an  Opinion. 

The  difficulties  in  judging  as  to  the  sanitary  condition 
of  a  water  from  an  estimation  of  the  number  of  colonies 
developed  by  the  employment  of  either  of  the  biological 
methods  are  in  the  present  state  of  our  knowledge  in- 
superable. It  is  undoubtedly  true  that  the  biological  is 
the  most  delicate  of  all  known  tests,  and  that  the  purer 
the  water,  cceteris  paribus,  the  smaller  the  number  of 
colonies  present.     It  is  equally  true,  howcA^er,  that  micro- 

1  Analyst,  April  1883. 


SAMPLE    OF    WATEE    SUBMITTED    TO    ANALYSIS       201 

organisms  are  to  be  found  in  nearly  every  water,  and 
that  length  of  storage,  temperature,  degree  of  aeration, 
etc.  of  a  water,  which  have  much  to  do  with  the  number 
of  colonies  present,  have,  of  course,  no  necessary  connec- 
tion with  pollution.  Prof  Bischof  found  :  ^  (1)  that  New 
Eiver  water  kept  for  six  days  compared  unfavourably,  as 
to  number  of  colonies,  both  with  New  Eiver  water  fresh 
from  the  mains,  to  which  1  per  cent  of  sewage  had  been 
added,  and  with  Thames  water  at  London  Bridge  {vide  page 
213);  (2)  that  the  production  of  colonies  is  aided  in  a  most 
marvellous  way  by  increase  of  temperature  from  the  freezing 
point  where  it  is  entirely  stop|)ed,  up  to  from  86°  to  104° 
F. ;  and  (3)  that  a  deficiency  of  oxygen  in  a  water 
checked  the  development  of  microphytes.  Until,  there- 
fore, it  becomes  possible  to  eliminate  the  effects  produced 
by  such  influences,  we  have  still  to  rely  very  much  on 
our  chemical  and  microscopical  methods  in  the  formation 
of  an  opinion,  availing  ourselves  of  any  corroborative 
evidence  which  biological  methods  may  afford. 

1.  The  amount  of  organic  matter  in  the  best  spring  P"i'est 

spring 
waters waters. 

Milligramme  Milligramme 

per  litre.  per  litre. 

Spring  -water  A.     Free  ammonia  "OOS.     Albuminoid  ammonia  "02. 
„     B.        „  „  -000.  „  „         -01. 

2.  A  good  water  for   drinking  purposes   should   not^°°^^g 
contain  more  than 

Milligramme  per  litre. 
Free  ammonia  .  .  .  .  "01  or  'OS. 

Albuminoid  ammonia      .  .        • .  '08 

3.  A  water  which  possesses  the  following  amounts  of  suspicions 
the  two  ammonias  is  classed  amongst  the  suspicious  waters. 

I  have  frequently  noticed  such  waters  as  belonging  to 

^  Paper  on  "  Dr.  Kocli's  Gelatine  Peptone  "Water  Test,"  read,  before  the 
Socy.  of  Med.  Ofiicers  of  Health  on  April  16,  1886. 


202      OPINION    AND    PEEPARATION    OF    REPORT    AS    TO 

shallow  wells  surrounded  by  soil  on  which  soapsuds,  etc., 
are  sometimes  thrown. 

Milligramme  per  litre. 
Free  ammonia  .  .  .  .         "01  or  -02. 

Albuminoid  ammonia       .  .  .         •12. 

The  suspicion  of  contamination  is  strengthened  if  the 
chlorides  (in  districts  where  these  salts  do  not  abound) 
and  nitrates  or  nitrites  (in  non- chalky  districts)  are  in 
excess.  An  excess  or  increase  of  the  amount  of  saline 
residue  is  of  unfavourable  omen  in  the  case  of  a  doubt- 
ful water,  for  polluted  waters  generally  contain  a  larger 
amount  than  pure  waters  coming  from  similar  sources, 
although  it  cannot  of  course  be  said  that  a  water  which 
is  higiily  saline  is  for  that  sole  reason  to  be  suspected. 

4.  A  water,  with  or  even  without  an  excess  of  free 
ammonia,  which  displays  a  larger  amount  of  albuminoid 
deinnation.  ammouia  than  '15  milligramme  per  litre,  should  always 
be  condemned  if  there  is  an  excess  of  nitrogen  as  nitrates 
and  nitrites  (in  non-chalky  districts),  and  an  excess  over 
the  average  of  the  district  of  chlorides.  If  the  nitrates 
and  nitrites  should  not  be  in  excess,  but  the  chlorides  be 
considerably  above  the  average  of  the  district,  the  water 
should  still  be  denounced  as  unfit  for  drinking.  If,  with 
the  above-mentioned  excess  of  organic  matter,  the  nitrates, 
nitrites,  and  chlorides  should  be  insignificant  in  quantity, 
we  should  not  form  so  unfavourable  an  opinion  of  the 
water,  but  would  suspect  the  organic  matter  to  be  of 
vegetable  origin — a  ^dew  which  would  be  strengthened 
or  rebutted  by  other  evidence,  such  as  that  derived  from 
a  microscopic  examination  of  the  deposit  from  the  water, 
the  colour  of  the  water  in  a  two-foot  tube,  etc. 


Waters  de- 
serving con 


SAMPLE    OF   WATER    SUBMITTED    TO    ANALYSIS       203 


Grains  per  Gallon. 

MiLLIORAMME  PER 

Litre. 

Water  from  spring  pond 
situated  in  middle  of 
a  meadow.     Water  al- 
ways    running     from 
pond. 

Chlorine. 

N  itrogen  as 

Nitrates  and 

Nitrites. 

Free 
Ammonia. 

Alb. 
Ammonia. 

4-5 

•1 

•08 

•18 

Waters 
fouled  by 
surface  im- 
purities. 


The  amount  of  chlorine  does  not  exceed  that  found  in 
the  purest  waters  of  the  district.  Entomostraca  noticed 
in  it.  Sediment  consists  of  confervse.  Such  a  water 
cannot  be  condemned,  but  would  simply  be  described  as 
somewhat  dirty.  If  the  spring  were  enclosed  by  brick- 
work, so  as  to  prevent  the  entrance  of  surface  impurities, 
the  water  would  be  perfectly  pure. 

Here  is  the  analysis  of  a  water  from  a  draw-well 
situated  close  to  a  dusty  highway  road,  in  a  district 
where  the  purest  waters  contain  an  excess  of  chlorine : — 


Grains  per  Gallon. 

Milligramme  per  Litre. 

B. 

Chlorine. 
6-3 

Nitrogen  as 

Nitrates  and 

Nitrites. 

•2 

Free  Ammonia. 
•01 

Alb.  Ammonia. 
•14 

Such  a  water  is  simply  fouled  to  some  extent  with  surface 
impurities.  If  a  pump  were  substituted  for  the  bucket, 
etc.,  the  water  in  all  probability  would  be  quite  pure. 

5.   If  a  water  exhibits  an  excess  of  free  ammonia  and^^j.^^.^ 
an   excess   of  albuminoid   ammonia,  with   an   excess   of  polluted 
nitrates   and   nitrites,  and  with  an   amount  of  chlorine  nVatte^r"!™^ 
above  the  average  of  neighbouring  waters,  that  water  is 
polluted  with  animal  organic  matter,  e.g. — 


204      OPIXIOX    AND    PKEPAEATION    OF    EEPORT    AS    TO 


Samples. 

Grains  per  Gallon. 

MiLLIGKAMME  PER  LiTRE 

=Part  pee  Million. 

Solids. 

Chlorine. 

Nitrogen 

as 
Nitrates 

and 
Nitrites. 

Free 
Ammonia. 

Alb. 
Ammonia. 

Waters  from  ^vells  pol- 
luted by  foul  soil  of 
ciLurchyard — 

A      .         .         . 

B      .         .         . 

Water  of  well  polluted 

by  manure  of  garden 

94 

11 

... 

Abundant 
Abundant 

2-4 

•12 

•4 

•12 

•32 
•52 

•20 

Waters  con-        6.  If  a  Water  possesses  a  large  excess  of  albuminoid 

with"ve'^e-    ammonia,  and  but  little  or  no  excess  of  free  ammonia, 

table  or-      and   an  insignificant   amount  of  chlorides  and   nitrogen 

°  salts,  there  is  strong  presumptive  evidence  that  the  water 

is  contaminated  with  vegdahle  organic  matter.      Such  a 

water  may  be  offensive,  even  after  filtration  through  the 

best  of  filters. 

E.g.  Well  Tvater  fouled  with  rotten 

leaves  ..... 

(A  little  rain  water  enters  tlie  well) 

Well  waters  rendered  impure  by  the 
decayed  roots  of  trees 

No  excess  of  nitrogen  as  nitrates  and  nitrites  in  either 
of  these  three  waters. 

Some  peaty  waters  are  an  exception  to  this  rule. 


Free 

ammonia, 

Milligramme 
per  litre. 
•05 

Alb. 

ammonia, 

•30 

A. 

B. 

Free 

ammonia, 

•01 

None. 

Alb. 

?) 

•37 

•25 

E.g.  Spring  on  Dartmoor,  Devon 
(water  very  brown) 

Waaler  from  peaty  well 


Milligramme  per  litre. 
Free  ammonia,  •OB 
Alb.  „         -11 

Free         „         -06 
Alb.  „         •OS 


Peaty  waters  often  yield  equal,  or  nearly  equal, 
amounts  of  free  ammonia  and  albuminoid  ammonia. 
When  equal,  or  nearly  equal,  amounts  of  albuminoid 
ammonia  pass  off  in  each  distillate,  strong  evidence  is 


SAMPLE    OF    WATEK    SUBMITTED    TO    ANALYSIS        205 


afforded  that  the  organic  matter  is  of  vegetable  origin, 
although  we  must  not  conclude  that  when  the  albuminoid 
ammonia  does  not  come  over  in  that  manner  that  the 
organic  matter  is  not  vegetable. 

Prof  Wanklyn  tells  me  that  he  found,  on  experimenting 
with  the  albumen  of  the  egg  and  the  gluten  of  wheat, 
this  very  important  difference,  as  regards  the  manner  in 
which  the  albuminoid  ammonia  often  yields  its  ammonia. 

Milligramme  per  litre. 

Vegetable  Organic  Matter.  Animal  Organic  Matter. 

•04  or  -03  -06  or  -07 

•03  „  -03  -03   „    -025 

•03  „  -03         '  -01   „   -005 

Dr.  Charles  Smart  thus  discriminates^  between  fresh  and 
decomposing  organic  matter  of  animal  or  vegetable  origin : — 


Okgaxic 

Matter. 

Eecent. 

Decomposing. 

Xitrogen  as  Alb.  Amm.  yielded  slowly. 

Nitrogen  as  Alb.  Amm.  yielded 
more  rapidly. 

Oxj'gen  required  by  Drs.  Letheby  and  Tidy's  Permang.  of  Potash  process. 

Animal. 

Vegetable. 

Animal. 

Vegetable. 

A  small  quantity. 

A  large  quantity. 

A  small  quantity. 

A  large  quantity. 

Colour  interference. 

None. 

Yellow    colour   on 
addition    of    soda 
carb.  to  water,  and 
a  greenish   colour 
with      Nesslerized 
distillates  {vide  p. 
41). 

Diagnosis  of  a  Peaty  Water. 
Colour. — Generally,  but  not  always,  a  shade  of  nntty  brown. 
Saline  Matters. — Small  in  quantity. 
Chlorine.  Do. 

Free  Ammonia. — Very  little    )  or  Equal,   or    nearly  equal,   in 
Alb.  Ammonia. — Excess  j  amount. 

Hardness. — Very  little. 

1  Op.  cit. 


Diagnosis  of 
a  peaty 
water. 


206       OPINION    AND    PEEPAEATION    OF   REPORT    AS    TO 

Nitrogen  as  Nitrates  and  Nitrites. — Nil,  or  almost  nil. 
Volatile  Matters. — On  burning  solid  residue,  very  little. 
Behaviour  of  Residue  during  Ignition. — It  blackens  in  patches  or 
waves,  which  colour  is  very  persistent. 
Oxygen  Absorbed. — Excess. 

N.B. — Water  often  contains  some  hydrogen  sulphide. 


Analyst. 

ExAiiPLES  OF  Water. 

Grains  per  Gallon. 

Part  per 

Million  = 

Milligramme 

PER  Litre. 

Solids. 

Volatile 
Matters. 

Chlorine. 

Kitrogen  as 

Nitrates  and 

Nitrites. 

Free 
Ainm. 

Alb. 
Amm. 

Dr.  Shea 
Do. 

Author 
Dr.  Shea 

1.  From  peaty  soil 

2.  From    peat    in 

sand 

3.  Peat       spring  ; 

hardness  2  or 
2^  degi-ees 

i    From  peat ;  soil 
contained  car- 
bonate of  iron, 
and    consisted 
of     a     chalky 
marl.      Water 
smelt  strongly 
of      hydrogen 
sulphide 

10-85 
6-05 

5-00 
29-35 

•95 

•85 

1-40 
1-57 

1-85 
1^4 

1^1 
1-2 

•25 
Kone. 

•02 

-065 
•04 

•03 

•08 

-085 
-06 

•11 

•06 

Pollution  by 
foul  gases. 


The  pollution  of  a  "water  by  sewer  gas  or  foul  gaseous 
emanations  from  faecal  matter  may  be  diagnosed  by  the 
absence  of  an  excess  of  chlorine  and  nitrogen  as  nitrates 
and  nitrites,  wliilst  there  is  an  excess  of  organic  matter, 
and  the  microscope  discloses  an  abundance  of  bacteria 
and  micrococci. 

The  knowledge  of  the  source  of  the  water  will  prevent 
the  possibility  of  making  a  mistake  between  a  water 
vitiated  with  vegetable  organic  matter  and  one  poisoned 
by  sewer  gases. 

7.  If  a  water  contains   an  enormous  excess  of  free 


SAMPLE    OF    WATER    SUBMITTED    TO    ANALYSIS        207 

ammonia    and   an   excess    of    albuminoid   ammonia,   the  waters 
strongest  evidence  is  afforded  that  a  cesspool  or  urinal  iSe°m,ement^ 
delivering  its  contents  into  the  well.      Urine  very  rapidly  matters, 
decomposes,  the  micrococcus  urete  converting  the  urea  into  diagnosis, 
carbonate  of  ammonia,  e.g. — 

Water  from  well  polluted  by  urinal : — 

Milligramme  per  Litre. 

Free  ammonia,  above  .  .         I'O 

Alb.  „  „  .  .  -35 

It  is  necessary  to  remember  that  rain  water  holds  in  solu- 
tion a  large  amount  of  free  ammonia,  derived  from  the 
air  which  it  washes  as  it  descends,  and  from  the  soot  with 
which  it  is  generally  mingled ;  and  that,  in  consequence 
of  the  uncleanliness  of  the  surfaces  that  collect  it,  which 
are  often  stained  with  the  excreta  of  birds,  it  is  apt  to 
exhibit  an  excess  of  albuminoid  ammonia.  It  is  desirable 
not  to  confound  the  water  of  a  well  polluted  with  urine 
with  water  commingled  with  sooty  rain  water. 

The  manner  in  which  the  free  ammonia  comes  over, 
and  the  collateral  evidence,  almost  render  such  an  accident 
impossible. 

On  distilling  ^  litre  of  rain  water  collected  on  a  slate 
roof  in  the  country,  which  presented  a  slightly  sooty 
appearance,  I  obtained  the  following  result : — 

Free  ammonia  '35 
•25 
•12 
•09 
•09 
•04 
■03 

•97 

I  took  off  7  distillates  of  5  0  c.  c.  each,  and  did  not  come 
to  the  end  of  the  free  ammonia  in  this  -l-  litre  of  water. 


208      OPIXIOX    AXD    PEEPAEATIOX    OF    EEPOET    AS    TO 

In  the  case  of  a  water  polluted  with  urine,  the  free  am- 
monia passes  over  in  a  \Yholly  different  fashion,  c/j.  in  \  litre. 

Free  arumonia    "38 
•14 
•065 
•035 


•620 


In  litre  above  I'O  part  per  million  =  milligramme  per  litre. 
Rainwater         There  is  One  point  of  resemblance  between  the  be- 

and  well  .  c  •  n  • 

water         haviour  of  ram  water  and  urine   polluted  water  under 
polluted  by  (^jigtillation,  which  is,  that  in  both  cases  the  evolution  of 

urme.  '  ' 

ammonia  cannot  often  be  brought  to  an  end. 

Prof.  Mallet  even  insists  that  "  the  value  of  the 
Wanldyn,  Chapman,  and  Smith  process  depends  more 
upon  watching  the  j/r ogress  and  rate  of  evolution  of  the 
ammonia  than  upon  determining  its  total  amount."  "  Tlie 
gradual  evolution  of  albuminoid  ammonia  indicates  the 
presence  of  organic  matter,  whether  of  vegetable  or  animal 
origin,  in  a  fresh  or  comparatively  fresh  condition,  whilst 
rapid  evolution  indicates  that  the  organic  matter  is  in  a 
j)utrescent  or  decomposing  state." 

The  following  differences  between  rain  water  and 
urine  polluted  water  should  also  be  borne  in  mind : — 

(«)  Particles  of  soot  may  generally  be  seen  in  rain  by 
the  naked  eye,  or  by  the  aid  of  the  microscope,  which  are 
absent  in  the  latter. 

(b)  The  latter  will  probably  contain  an  excess  of 
nitrates  unless  actual  sewage  pollutes  the  water,  whilst 
the  former  w^ill  probably  exhibit  only  a  trivial  amount,  or 
none. 

(c)  The  latter  will  possess  an  excess  of  chlorine,  whilst 
rain  will  not,  unless  it  falls  near  the  sea. 

{d)  The  latter  will  display  a  greater  or  less  degree  of 
hardness,  whilst  the  former  will  be  soft. 


SAMPLE    OF    WATER    SUBMITTED    TO    ANALYSIS        209 


Diagnosis  of  Pollution  by  Urine  or  by  Slop  and 
Sink  Water. 

Free  Ammonia. — Overwlieliiiing  amount,  from   -50  to  2  milli- ^'^giiosis 

, . ,  of  Pollution 

grammes  per  litre.  ty  siops^ 

Albuminoid  Ammonia. — Excessive.     Often  about   '3  or   "4,  or  etc. 
even  "6  milligramme  per  litre. 

Chlorine. — Generally  in  large  excess. 

Nitrogen  as  Nitrates  and  Nitrites. — In  either  minute  amount,  or 
in  large  excess. 

Oxygen  absorbed. — Excess. 


Analyst. 

Examples. 

Grains  per  Gallon. 

Milligramme 

PER  Litre  = 

Part  per 

Million. 

Remarks. 

Solids. 

Volatile 
Matters. 

Chlor- 
ine. 

Alb. 
Amm. 

Free 
Amm. 

Dr.  Shea 

Aiitlior 

Author 
Author 

"Water     from     well 
close    to    broken 
sink  pipe 

Water  from  artesian 
well    into    which 
drain    conveying 
urine  from  stable 
leaked 

Same    after    diver- 
sion of  drain 

Water  from  a  Shallow 

Well. 
Before  "i 

Pollution  by 
-  f'.ontents  of 
Drain. 

After     J 

50 

75-6 
103 

2 

Nitrogen  as 

Nitrates  and 

Nitrites. 

Xone 
Abundant 

9 

8-2 

7-3 

12-3 
16 

Very 
abund- 
ant 

•51 

■Oi 

•01 
•69 

•35 
•31 

•08 

•07 
•28 

The  com- 
paratively 
small  pro- 
portion of 
free  am- 
monia was 
due  to  the 
admixture 
of  the  urine 
with  a  vast 
quantity  of 
water  in 
this  deep 
well. 

Persistent 
uncontroll- 
able diar- 
rhoea pro- 
duced. 

210      OPINION    AND    PEEPAEATION    OF    EEPOKT    AS    TO 

Dr.  Shea  has  kindly  sent  me  particulars  of  an  interest- 
ing case  where  a  new  cesspool  was  constructed  about 
thirty  yards  from  a  well,  to  receive  slop  water.  Fourteen 
days  after  its  completion  the  water  of  the  well  was  noticed 
to  taste  unpleasantly.  On  analysis  it  proved  to  contain 
neither  free  nor  albuminoid  ammonia  in  excess,  for  the 
intervening  earth  acted  as  a  filter.  No  less  than  17 "5 
grains  per  gallon  of  chlorine  were  found  in  it,  whilst 
neighbouring  unpolluted  wells  possessed  only  1*5  to  2'3 
grains  of  chlorine  per  gallon. 


Diagnosis  of  Pollution  by  Contents  of  Cesspools  and 
Sewers. 

Diagnosis  A  glaiicc  at  the  following  examples  of  waters  polluted 

h  ^ewagT  ^y  ^  cesspool  and  drain,  and  by  soil  containing  a  large 

excess  of  decomposing  animal  matters,  reveals  immediately 

the  difference  in  the  results  obtained. 


Samples. 

Grains  per  Gallon. 

Milligramme 

PER   JjITRE  = 

Part  per 
Million. 

Remarks. 

Solids. 

Chloi-iue 

Nitrogen 

as  Nitrates 

and 

Nitrites. 

Free 
Amm. 

Alb. 
Amni. 

Water  from 
shallow 
well    near 
K.  H.  B. 

Water  from 
shallow 
well  at  A. 
L.  B. 

101 

50-4 

12-5 
6-9 

excess 
none 

Above 
1-0 

Above 
1-0 

•24 

•50 

Polluted  by  leaky 
cesspool.  Tj'phoid 
fever  and  diph- 
theria amongst 
the  owners. 

Accidental  overflow 
into  well  of  cess- 
pool contents 
which,  having 
been  the  '  reci- 
pient of  the  spe- 
cific poison  of 
typhoid,  spread 
the  disease. 

SAMPLE    OF    "WATER    SUBMITTED    TO    AXALYSIS        211 

Free  Ammonia. — In  large  excess. 

Albuminoid  Ammonia. — In  excess. 

Chlorine  somewhat  in  excess,  but  not  so  marked  as  when  slop 
water  is  the  polluting  agent. 

Nitrogen  as  Nitrates  and  Nitrites. — If  sewage  passes  directly  into 
a  well — none.  If  sewage  travels  through  some  intermediate  earth 
— generally  an  excess. 

Oxygen  absorbed. — Large  excess. 

8.  "Waters  of  shallow  wells  or  springs  in  towns  (the  unsafe 
soil  of  which  is,  for  the  most  part,  more  or  less  filthj)  or^^*^^" 
near  chiu'chvards,  if  found  to  contain  an  excess  of  solid 
residue,  in  the  form  of  nitrates  and  nitrites,  chlorides, 
sulphates,  and  phosphates,  should  be  pronounced  as  unsafe ; 
although  the  amount  of  free  and  albuminoid  ammonia  may 
be  insignificant,  for  we  can  never  tell  when  the  earth  may 
cease  to  act  as  a  filter  by  oxidizing  the  filth. 

In  forming  an  opinion  as  to  the  condition  of  a  water, 
we  should,  in  weighing  the  e^ddence  afforded,  adhere 
strictly  to  the  standard  of  pure  drinking  water  of  the 
district  from  which  the  sample  is  collected.  "We  should 
be  extra-exacting  as  to  purity  in  judging  of  a  river 
water  that  has  been  polluted  at  some  points  of  its  course 
with  the  manure  of  fields  and  indescribable  filth,  for  these 
river  waters  contain  every  now  and  then  undigested  por- 
tions of  food  excreted  from  the  human  intestinal  canal,  in 
addition  to  living  organisms  visible  by  the  aid  of  the 
microscope,  as  well  as  the  accompaniments  of  all  life  in 
water — namely,  dissolved  and  suspended  organic  matter 
on  which  these  same  organisms  feed.  Septic  poisons,  or 
the  poisons  of  the  zymotic  diseases,  attach  themselves  to 
organic  filth  undergoing  putrefactive  decomposition,  in 
which  they  find  an  appropriate  nidus  for  development. 
It  is  questionable  whether  such  rivers  should  ever  be 
employed  as  public  supphes,  for,  if  the  sewage  of  towns 
and  villages  on  their  banks  be  diverted  and  utilized  on 
the  land,  the  washings  of  manured  fields  cannot  during 


212      OPINION    AND    rKEPARATION    OF   REPORT    AS    TO 

periods  of  flood  be  altogether  excluded.  If  such  rivers  are 
used  for  drinking  purposes,  an  extra  degree  of  purity  should 
be  demanded  of  the  water  companies  that  supply  them. 

D.  Preparation  of  Eepoet, 

Report  of  Ths  opiniou  of  a  water  having  been  formed  on  a  sound 

opinion.  ij^gj^g^  j^g  delivery  is  a  very  simple  matter.  In  conse- 
quence of  the  severity  of  the  criticisms  that  have  been 
made  as  to  the  reliability  of  the  several  processes  of  water 
analysis,  and  as  to  the  diagnosis  with  certainty  between  a 
small  amount  of  vegetable  and  animal  impurity  in  a  water, 
certain  analysts  are  very  guarded  in  the  choice  of  the 
language  employed  in  the  delivery  of  an  opinion  and 
express  themselves  thus : — "  This  appears  to  be  a  pure 
sample "  and  "  slioivs  no  evidence  of  contamination  from 
organic  matter  of  animal  origin  "  ;  "  the  polluting  material 
is  of  a  highly  nitrogenous  character,"  etc.  The  modes  of 
statement  of  the  results  of  water  analysis  are  so  various 
that  they  produce,  even  amongst  medical  men,  endless 
confusion,  "  Chlorine  calculated  as  chloride  of  sodium," 
"  Loss  on  ignition  after  deducting  combined  carbonic  acid," 
are  samples  of  the  most  recent  eccentricities.  Wliy  all 
chlorides  in  drinking  water  should  be  entered  as  common 
salt,  and  why  combined  carbonic  acid  should  be  alone 
excluded  from  the  loss  on  incineration,  are  peculiarities 
for  which  it  is  quite  impossible  to  find  any  valid  reason. 
Some  analysts  express  themselves  in  parts  per  100,  a  few 
in  10,000,  others  in  70,000  or  in  100,000,  or  in  parts  per 
million,  whilst  others  make  an  estimate  in  grains  per  gallon 
or  milligrammes  per  litre.  Oxidized  compounds  of  nitrogen 
are  entered  by  some  as  nitric  acid,  by  others  as  nitrates,  and 
by  the  majority  as  nitrogen  in  the  forms  of  nitrates  and 
nitrites.  ^    In  order  to  prevent  such  differences  in  the  modes 

^   Vide  ' '  Rules  for  Interchange  of  Different  Expressions  of  Results  of 
Analysis,"  in  Appendix. 


SAMPLE    OF   WATER    SUBMITTED    TO    ANALYSTS       213 


of  expression  of  the  results  of  an  analysis  which  occasion  so 
much  annoyance  amongst  the  public,  one  uniform  plan  of 
drawing  up  reports  should  be  universally  adopted.  A  form, 
of  the  accompanying  description,  is  convenient  for  conveying 
a  report  to  the  sanitary  authority  or  other  applicant : — 

Sanitary  Authority. 

1S8 


Analytical  Report. 


NAME  AND  DBSCEIPTION  of 
THE  SAMPLE  OF  Water. 

Grains  per  Gallon. 

Parts  per 
Million.l 

Hard- 
ness. 

Depnsit 
luader 
Mior<j- 
scope. 

Mem. 

1 

S 

1%. 

o  CS 

0-" 

tr,  o 
< 

1 

W 

a 
< 

W 

LONDON  WATER   SUPPLY 
(Thames)         .... 
(New  River)    .... 
(Kent  Company)     . 

Very  bad  Water.  Tliames  Water 
at  London  Bridge  . 

Pure  Spring  Water  which  sup- 
plies   village    of    Woodham 
Walter 

Good  Water  from  Shallow  Well 
depth  25  feet  .... 

Good    Waters    from    Artesian 
Wells,    of    ditlerent    depths, 
which  supply  a  Village  . 

18-5 
17-7 
26-5 

21 

30 
( 106-4 

1   98-0 

1-2 
1-1 

2-1 

2-4 

7 
37-7 

37-6 

•15 
■17 
•30 

4-00 

•20 

-07 
•03-1 

■00  j 

•06 
04 
■01 

•04 

0-01 
0^00 
0^01 

1-02 

0-00 

0-01 
0-01 

0-63 

0-03 
0^06 
0^02 

0-59 

o-oi 

0-05 
0^02 

0^01 

14 
15 
21 

6 

13 

9i 

Memoranda  as  to  Water  Analysis. 

1.  Anyone  who  wishes  to  have  his  or  her  drinking  Water  analyzed  a<i/iePM6^ic  Expense, 

should  apply  to Clerk  of  the 

Sanitary  Authority,  for  an  order  from  this  Authority,  giving  the  reasons  for  his  or 
her  request.  If  the  Authority  considers  that  some  grounds  exist  for  thinking  that 
the  Water  has  produced  disease,  or  is  likely  to  Ise  injurious  to  health,  the  Authority 
will  issue  instructions  through  its  Clerk  to  the  Medical  Officer  of  Health,  who  will 
on  receipt  of  the  sample  from  the  Inspector  of  Nuisances,  analyze  the  water  as 
soon  as  possible,  and  communicate  the  result  to  the  applicant. 

2.  Any  Member  of  either  of  the  Combined  Sanitary  Authorities,  and  any  qualified  medi- 

cal man  practising  in  the  Combined  Districts  who  wishes  to  have  his  own  drinking 
Water  analyzed,  should  communicate  direct  with  the  Medical  Officer  of  Health. 

3.  Any  qualified  medical  man  practising  in  the  Combined  Districts,  who  considers  it 

expedient  that  the  Drinking  Water  of  a  Patient  on  whom  he  is  in  attendance  should 
be  Analyzed  at  the  Fuhlic  Expense,  should  communicate  direct  with  the  Medical 
Officer  of  Health. 

^  As  it  is  not  easy  to  carry  in  the  memory  quantities  smaller  than  are 
represented  by  the  second  point  of  decimals,  it  is  undesirable  to  express 


214       SAilPLE    OF    WATER    SUBMITTED    TO    ANALYSIS 

the  amount  of  ammonia  and  albuminoid  ammonia  in  fractions  of  a  grain 
per  gallon,  -whicli  have  not  easy  or  ready  significance,  as  has  been  adopted 
by  the  Society  of  Analysts  whose  form  of  certificate  is  here  subjoined.  This 
form  is  in  other  respects  good,  but  is  more  adapted  to  the  detailed 
requirements  of  the  professional  analyst  than  to  the  needs  of  the  health 
officer. 


SOCIETY  OF  PUBLIC  ANALYSTS 


EEPORT   OF   ANALYSIS   OF- 


-WATER,   DRAWN  ON. 


A11  results  are  expressed  in  Grains  per  Gallon. 


p. 

s 

C3 
CQ 

O 
C! 

_o 
S 

CD 
P 

O 

=2 
1 

H 

3 
< 

o 
^  o 

o 

1 

o 

s 

1 

g 

o 

f-l 

'3 
o 

s 

1 

.2 
'S 

o 

S 
S 

'o 
S 

OXTGEN, 

Absorbed  in 

Hardness, 
Clark's  Scale, 
in  degrees. 

1" 

c 

s 

< 

1 

a 

> 

+3 

go 

13 

'S 

a 

60 
'0 

a 

Analyst's  Signature,. 


Late  of  Reports 


It  may  be  remarked  throughout  this  work  thatjat  times  grains  per  gallon 
are  referred  to,  sometimes  septems  and  deci-gallons,  whilst  at  others  the 
metrical  system  is  employed.  The  object  in  view  is  to  render  the  Medical 
Officer  of  Health  perfectly  au  fait  in  the  interchange  of  one  into  the  other, 
as  it  is  necessary  for  him  to  be  conversant  with  all  the  methods  of  calcula- 
tion in  use. 


CHAPTEE    XVI 

CONCLUDING   REMAEKS    ON    SECTION    I 

Eeadees  of  the  foregoing  pages  will  have  perceived  that  concluding 
I  do  not  recommend  the  complicated  and  tedious  process 
of  Frankland  and  Armstrong,  and  that  I  cannot  advise 
the  sole  unaided  adoption  of  the  beautiful  process  of 
Wanklyn,  Chapman,  and  Smith,  nor  exclusive  reliance  on 
the  quantitative  Forchammer  permanganate  of  potash  pro- 
cess, which  is  often  misleading.  Whilst  agreeing  with  the 
inventors  of  the  first  process  as  to  the  necessity  of  regard- 
ing the  amount  of  nitrogen  as  nitrates  and  nitrites  in  a 
water,  I  totally  disagree  with  Mr.  "Wanklyn  in  relying 
solely  on  the  indications  of  the  ISTessler  test,  to  the  exclu- 
sion of  an  estimation  of  these  products  of  oxidation  and 
other  valuable  data  on  which  an  opinion  should  be  based. 
Fallacies,  undoubtedly,  attend  Dr.  Frankland's  lengthy 
method,  and  Mr.  Wanklyn's  rapid  method ;  and  errors  are 
associated  with  the  quantitative  permanganate  of  potash 
processes,  whatever  those  who  are  disciples  of  these  several 
methods  may  think  to  the  contrary.  I  am  myself  indebted 
to  each  process,  more  especially  to  Mr.  Wanklyn's,  in  my 
studies  of  water  analysis.  The  methods  which  I  practise 
and  recommend,  and  which  I  have  in  the  foregoing  pages 
attempted  briefly  to  describe,  are,  it  will  be  perceived, 
modified  forms  of  the  Wanklyn,  Chapman,  and  Smith 
process  and  of  the  quantitative  Forchammer  or  oxygen 
process.     I  am  not  conscious  of  ever  having  made  a  mis- 


216  ■  CONCLUDING    EEMAEKS 

take  in  water  analysis.  This  success  is  not  attributable 
to  any  exceptional  skill,  but  to  the  excellence  of  the  pro- 
cess, which  I  designate  the  "  Medical  Officer  of  Health 
Method,"  because  it  is  particularly  suited  to  his  wants. 

Eecipes  of  Standard  Solutions,  etc. 
Nesshr  Reagent. 

Dissolve,  by  heating  and  stirring,  35  grammes  of 
iodide  of  potassium  and  13  grammes  of  corrosive  sub- 
limate in  about  800  c.  c.  of  distilled  water.  Add 
gradually  a  cold  aqueous  saturated  solution  of  corrosive 
sublimate,  until  the  red  colour  produced  just  begins  to 
be  permanent.  Add  160  grammes  of  solid  caustic 
potash  to  the  mixture,  which  is  then  to  be  diluted  with 
sufficient  water  to  bring  the  whole  to  a  litre.  To  render 
the  test  sensitive  add  a  little  more  cold  saturated  solution 
of  corrosive  sublimate  and  allow  it  to  settle. 

This  reasjent  is  a  rather  troublesome  one  for  the 
Medical  Officer  of  Health  to  make,  and  that  prepared  by 
different  persons  varies  somewhat.  It  is  desirable  that 
every  one  should  obtain  his  ISTessler  test  from  one  and 
the  same  source,  but  this  arrangement  seems  very  difficult 
of  attainment.  Very  good  is  to  be  procured  direct  from 
Messrs.  Sutton  of  ISTorwich,  or  indirectly  through  Messrs. 
Townson  and  Mercer  of  Bishopsgate  Street,  London. 

Standard  Soai^  Solution. 

10  grammes  of  Castile  soap  are  dissolved  in  a  litre 
of  weak  alcohol  (35  per  cent).  If  35  per  cent  alcohol 
is  not  readily  procurable,  it  may  easily  be  prepared  by 
mixing  29  ounces  and  15  minims  of  distilled  water 
with  17  ounces  and  30  minims  of  rectified  spuit 
(generally  84  per  cent),  which  is  everywhere  obtainable. 


CONCLUDING   REMARKS  21  7 

One  c.  c.  precipitates  one  milligramme  of  carbonate  of 
lime. 

This  standard  solution  will  not  remain  unchanged  for 
an  indefinite  time.  It  loses  strength.  It  is  wise  to 
make  a  small  quantity  of  fresh  solution  every  three  or 
four  months.  One  and  the  same  water  was  recently 
examined  by  me  for  hardness  with  different  standard 
soap  solutions  of  various  ages,  and  the  following  results 
were  obtained : — 

(a)  19 1  degrees. 

(b)  17         „ 

(c)  16         „ 

(d)  18         „ 

(e)  17         „ 

It  is  useful  sometimes  to  verify  the  strength  of  a  soap 
standard  solution  by  the  help  of  a  solution  of  pure  fused 
cliloride  of  calcium,  I'll  gramme  in  a  litre  of  water. 
One  c.  c.  of  the  standard  soap  solution  should  precipitate 
1  milligramme  of  carbonate  of  lime,  which  is  the  exact 
amount  present  in  1  c.  c.  of  the  cliloride  of  calcium 
verifying  solution. 

Dilute  Standard  Solution  of  Ammonia. 

Keep  two  solutions — a  strong  and  a  dilute.  To  pre- 
pare the  strong  solution  dissolve  3  "15  grammes  of 
crystallized  sal.  ammoniac  in  1  litre  of  distilled  water. 
To  prepare  the  dilute  solution  place  5  c.  c.  of  the  strong 
solution  in  a  half-litre  flask,  and  fill  it  up  with  distilled 
water. 

Mingle  very  thoroughly  by  pouring  the  mixture 
several  times  from  the  flask  into  the  bottle,  and  from 
the  bottle  back  again  into  the  flask.  The  dilute  solution 
contains  ywu  niilligramme  in  each  cub.  cent. 

These  solutions  should  be  perfectly  limpid.  They 
will  not  remain  unaltered  for  an  indefinite  time.      If  any 


21"8  CONCLUDING    KEMARKS 

white  filaments  are  visible  in  them,  fresh  solutions  should 
be  prepared. 

Permanganate  of  Potash  and  Caustic  Potash  Solution, 

Permanganate  of  potash  crystallized,  8  grammes ; 
solid  caustic  potash  in  sticks,  200  grammes ;  distilled 
water,  1  litre.  Boil  the  above,  so  as  to  thoroughly  dis- 
solve the  chemicals  in  the  water,  and  until  about  ^  of 
the  solution  has  passed  off"  as  steam  to  dissipate  all 
ammonia.  Eeplace  the  water  lost  in  boiling,  as  steam, 
by  adding  sufficient  distilled  water  to  bring  it  back  to 
the  litre. 

This  solution,  notwithstanding  the  greatest  precautions 
in  its  manufacture,  invariably  contains  more  or  less 
ammonia.  50  c.  c.  of  it  should  accordingly  be  distilled 
in  -|-  litre  of  twice  distilled  water,  and  the  ammonia  that 
is  estimated  must  be  abstracted  from  the  results  of  each 
analysis  of  a  water.  It  is  desirable  to  write  the  correc- 
tion on  the  label  of  the  bottle. 

Standard  Solution  of  Nitrate  of  Silver. 

Dissolve  4"79  grammes  of  crystallized  nitrate  of  silver 
in  1  litre  of  distilled  water.  One  c.  c.  precipitates  1 
millioframme  of  chlorine. 


SECTION  II 


SANITAKY  EXAMINATION 


OF 


A I  Pi. 


CHAPTEE   XVII 

THE    PUKITY    OF    AIR 

The  exammation  of  air  for  sanitary  purposes  by  tlie 
Medical  Officer  of  Healtli  may  be  deemed  by  some  as  work 
that  is  needless,  and  which  can  be  turned  to  no  practical 
advantage.  If  preventive  medicine  and  sanitation  is  ever 
to  become  an  exact  science,  we  must,  as  those  who  are 
laying  its  foundations,  be  able  to  state  in  precise 
language  the  boundary  lines  between  wholesome  air,  air 
to  which  it  is  undesirable  to  be  frequently  exposed,  and 
air  which  is  so  impure  as  to  be  quite  unfit  for  breathing  ; 
and,  again,  between  the  latter  and  that  which  is  poisonous. 
It  is  as  desirable  to  know  the  composition  of  the  air  we 
breathe  as  of  the  water  we  drink.  Indeed,  it  is  more 
important  to  attend  to  the  cleanliness  of  a  medium  in 
which  we  are  always  bathed,  and  which  is  continually 
passing  into  and  out  of  our  bodies,  than  of  that  which  is 
only  occasionally,  and  by  some  rarely,  introduced  into  an 
organ  which  contains  a  fluid  possessing  a  certain  anti- 
septic and  destructive  power  over  substances  injurious 
to  health.  The  insidious  and  indistinctly  recognizable 
deleterious  effects  on  the  health  of  a  continued  exposure 
of  the  human  frame  is  often  more  marked  in  the  case  of 
impure  air  than  of  impure  water.  The  train  of  evils  is 
so  slowly  but  surely  laid  as  to  even  escape  the  observa- 
tion often  of  an  experienced  medical  man,  who  sees  in  a 


222  THE    PUEITY    OF    AIR 

case  of  blood  deterioration  by  impure  air  one  of  imperfect 
or  defective  assimilation,  anaemia,  dyspepsia,  hysteria, 
disordered  biliary  functions,  or  one  of  those  indefinite  and 
chronic  ailments  which  lead  the  way  to  the  development 
of  some  visceral  disease.  What  a  contrast  is  afforded  by 
placing  a  representative  of  the  rebreathed  and  otherwise 
vitiated  air  trades,  who  perhaps  rarely  sees  the  sun,  by 
the  side  of  one  whose  daily  occupations  are  such  as  to 
give  him  the  fullest  benefit  of  the  purest  air  and  the 
freest  exposure  to  solar  light !  Bookbinders,  or  factory 
girls,  or  miners,  from  one  of  our  towns  and  colliery 
districts,  neither  of  whom  are  exposed  to  any  distinctly 
poisonous  influences,  may,  for  example,  be  compared  with 
sailors.  The  former  are  pallid,  jaded,  sallow,  afraid  of 
fresh  air,  with  uncertain  and  capricious  appetites,  the 
normal  functions  of  the  body  liable  to  continual  disturb- 
ance, excitable,  generally  affected  with  a  craving  for 
stimulants — alcohol  in  the  male,  tea  in  the  female — to 
temporarily  alleviate  their  sensations  of  depression,  whose 
lives  are  brief,  their  average  duration  being  known  by  all 
insurance  companies  with  mathematical  precision ;  whilst 
the  latter — namely  the  jack  tars — present  a  tout  cnseivMe 
indicative  of  the  highest  degree  of  health  and  buoyancy 
of  spirits,  which  is  so  well  known  as  not  to  need  descrip- 
tion. The  sailor  likes  his  occasional  drinking  bout  when 
he  goes  on  shore  to  enjoy  freedom,  after  the  confinement 
and  tedium  of  a  voyage,  but  is  no  "  soaker."  The  moral 
condition  of  a  class  is  intimately  associated  with  its 
physical  state,  but  a  consideration  of  this  connection 
would  lead  us  too  far  away  from  the  scope  of  these 
pages. 

The  late  Kegistrar- General,  Dr.  Farr,  drew  the  atten- 
tion of  the  public  some  years  ago  to  the  recognized 
statistical  law  that  the  mean  duration  of  life  decreased  as 
the  proximity  of  one  individual  to  another  increased. 


THE    PUPJTY    OF    AIR 


223 


Proximity. 

Mean  Duration  of  Life 

147  yards 

51 

years. 

139      „ 

45 

97      „ 

40 

46      „ 

35 

28      „ 

32 

17      „ 

.        29 

7      „ 

(Liverpool) 

26 

He  stated  that  in  23  towns  of  this  country  tliere  are 
3  8  persons  to  an  acre,  and  he  suggested  tliat  the  municipal 
bodies  and  local  boards  of  our  cities  and  towns  should 
establish  a  bye-law,  prohibiting  the  future  building  of 
houses  which  would  render  the  density  of  population  in 
excess  of  tliis  limit. 

Medical  Officers  of  Health  should  be  in  a  position  to 
state  accurately,  when  required,  if  any  given  air  is  or  is 
not  deleterious  to  the  health  of  the  body  continually  or 
frequently  exposed  to  its  influence.  Provided  that  they 
could  positively  lay  down  the  limit  beyond  which  the 
organic  matter  and  carbonic  acid  of  our  rooms,  in  which 
the  majority  of  us  spend  the  greater  portion  of  our  lives, 
should  not  pass,  then  architects  and  inventors  would 
soon  find  out-  some  simple,  efficient,  and  economical  mode 
of  ventilating  our  houses  and  public  buildings,  which  are 
nearly  all  afflicted  with  filthy  air ;  and  our  mortality 
from  diseases  which  we  know  now  to  be  indirectly 
preventible,  or  capable  of  considerable  reduction,  such  as 
consumption,  bronchitis,  and  other  pulmonary  affections, 
would  be  materially  lessened. 

Pure  air  contains  the  followina;  bodies : — 


224  THE    PURITY    OF    AIR 


Composition  of  Air. 

Composition  Oxygen  (Ozone,  an  active  form  of  Oxygen,  .  ^ 

of  pure  Air.  which  varies  in  amount).  .        209-6  (^§ 

Nitrogen      .  .  .  .  .  .        790- 

Carbonic  Acid       .....  "4 

Moisture  varying  with  temperature. 

Peroxide  of  Hydroqen        1  .       i 

,-r.^  7  Tvr-^  •     ^  •  7   r  occasional  components. 

JSitrous  and  JSitric  Acids  j 

Organic  Matter )  •     ,     . 

.  .  >■  very  mmute  traces. 

Ammonia  j        '' 

The  purest  air  is  to  be  found  on  mountains,  moors,  or 
far  away  from  contaminating  and  polluting  agencies, 
such  as  aggregations  of  men  and  annuals,  manufactories, 
etc.  There  is  an  ample  provision  in  nature  for  destroying 
the  impurities  of  the  air  produced  by  man,  especially  the 
organic  substances,  some  kinds  of  which  become,  when 
they  decompose,  injurious  and  often  dangerous  to  him. 
Ozone,  peroxide  of  hydrogen,  and  nitrous  acid,  are  the 
three  great  purifying  agents  contained  in  the  air,  the  first 
named  being  nearly  always  present  in  greater  or  less 
quantity,  the  two  latter  being  the  special  productions  of 
what  the  G-ermans  call  the  "  nieder-schlage,"  or  the  great 
cleansing  operations  of  nature,  such  as  the  precipitation 
of  the  air  -  washer  rain,  storms,  hail,  dew,  falls  of 
snow,  etc. 
Oxygen.  Oxygcn. — The  following  results  of  analyses  made  by 

M.  Eeynault  and  Dr.  A.  Smith  show  the  deviation  from 
a  state  of  purity  of  air,  as  respects  its  life-supporting 
constituent,  oxygen  gas,  in  different  situations  and  under 
different  circumstances : — 


THE    PUEITY    OF   AIR 


225 


Oxygen  in  Air — Summary  of  Averages. 


By  Mons.  Eeynault. 
Specimens. 

100  from  Paris     ..... 
9     ,,     Lyons  and  around  . 

30     ,,     Berlin 

10     „     Madrid  .... 

23     ,,     Geneva  and  Switzerland  . 
15     ,,    Toulon  and  Mediterranean 
5      ,,    Atlantic  Ocean 

1  ,,    Ecuador  .... 

2  „    Pichincha,    higher    than    Mont 

Blanc  .... 

Mean  of  all  foregoing 

„       the  Paris  specimens 


Yolume  per  cent, 
from  20-913  to  20-999 
„  20-918  to  20-966 
„  20-908  to  20-998 
„  20-916  to  20-982 
„  20-909  to  20-993 
„  20-912  to  20-982 
„  20-918  to  20-965 
„  20-960 

„      20-949  to  20-981 


20-949  to  20-988 
20-96 


20 


By  Dr.  Angus  Smith. 

N.E.,  seashore  and  open  heath  (Scotland) 

Atlantic,  lat.  43°  5',  long.   W.    17°  12' 

Top  of  hills  (Scotland)  .... 

In  a  suburb  of  Manchester  in  wet  weather    . 
Do.  do.  do. 

In  the  outer  circle  of  Manchester,  not  raining 

Low  parts  of  Perth    ..... 

Swampy  places,  favourable  weather 

In  fog  and  frost  in  Manchester     . 

In  a    sitting-room    which    felt   close,   but    not 
excessively  so    . 

Best  ventilated  wards  in  three   London  hospitals- 
Day      

Midnight       ...... 

Morning         ...... 

In  a  small  room  with  petroleum  lamp 

Ditto,   after  six  hours  .... 

Pit  of  theatre,  11.30  p.m 

Gallery,  10.30    p.m 

About  backs  of  houses  and  closets 

In  large  cavities  in  metalliferous  mines  (average  of 

In  a  schoolroom  ..... 

Court  of  Queen's  Bench,  February  2,  1866    . 

Q 


Volume  per  cent. 

.  20-999 

.  20-99 

.  20-98 

.  20-98 

.  20-96 

.  20-947 

.  20-935 
922  to  20-95 

.  20-91 

.  20-89 


20-92 

20-886 

20-884 

20-84 

20-83 

20-74 

20-86 

20-70 

20-77 

20-64 

20-65 


many) 


226 


THE    PURITY    OF    AIR 


Volume  per  cent. 

.      20-49 

ny) 

20-424 

20-14 

18-5 

18-27 

17-2 

.      20-92 

20 

86 

.      20 

77 

20 

85 

20 

78 

.      20 

75 

.      20 

79 

.      20 

81 

Court  of  Queen's  Bench,  at  Lantern 

Under  shafts  in  metalliferous  mines  (average  of  many) 

In  sumps  or  depressions  in  do.     . 

"When  candles  go  out  .... 

The  worst  specimen  yet  examined  in  a  mine  . 

Very  difficult  to  remain  in  for  many  minutes 

By  Various  Scientific  Chemists. 

Heidelberg  (mean  of  28  analyses)  Bunsen 

Paris.     Dumas  and  Boussingault  ^ 

Faulhorn.  Do. 

Brussels.     M.  Stas 

Geneva.      M.   Marignac 

Bern.     M.  Brunner    , 

Groningen.     Verver   . 

Copenhagen 


Herr  Von  Jolly  concludes  from  liis  experiments  in  the 
neiglibourliood  of  Munich,  that  the  variations  in  the  amount 
of  oxygen  contained  in  pure  air  are  influenced  by  the  direc- 
tion of  the  wind.  He  found  the  highest  proportion  of 
oxygen  with  a  steady  polar  current  and  the  lowest  with 
currents  from  the  equatorial  regions  where  processes  of 
oxidation  preponderate.  The  remarks  that  accompany 
Dr.  A.  Smith's  analyses,  dealing  as  they  do  with  a  point 
that  I  have  long  wished  to  press  on  the  attention  of  the 
sanitary  public,  are  worthy  of  weighty  consideration. 
Some  people  will  probably  inquire  why  we  should  give  so 
much  attention  to  such  minute  quantities^ — between 
20-980  and  20-999 — thinking  these  small  differences 
can  in  no  way  influence  us.  A  little  more  or  less  oxygen 
might  not  affect  us ;  but  supposing  its  place  occupied  by 
hurtful  matter,  we  must  not  look  on  the  amount  as  too 
smaU.  Subtracting  0-980  from  0-999,  we  have  a  differ- 
ence of  190  in  a  million.  In  a  gallon  of  water  there  are 
70,000  grains ;  let  us  put  into  it  an  impurity  at  the  rate 

^  Annalcs  de  Chimie   1841. 


THE    PUKITY   OF    AIR  227 

of  190  in  1,000,000  ;  it  amounts  to  13"3  grains  in  a 
gallon,  or  0'19  gramme  in  a  litre.  This  amount  would 
be  considered  enormous  if  it  consisted  of  putrefying 
matter,  or  any  organic  matter  usually  found  in  waters. 
But  we  drink  only  a  comparatively  small  quantity  of 
water,  and  the  whole  13  grains  would  not  be  swallowed 
in  a  day,  whereas  we  take  into  our  lungs  from  1000  to 
2000  gallons  of  air  daily.  If,  by  inhalation,  we  took  up 
at  the  rate  of  13  grains  of  unwholesome  matter  per  day 
— half  a  grain  per  hour — we  need  not  be  surprised  if  it 
hurt  us.  Such  an  amount  is  an  enormous  dose  of  some 
poisons,  and  yet  this  is  not  above  one  two-thousandth 
part  of  a  grain  at  every  inhalation.  It  is  marvellous 
what  small  amounts  may  affect  us,  even  when,  by  repeated 
action,  they  do  not  cumulate  as  certain  poisons  do.  We 
commenced  by  assuming  very  small  shades  of  difference 
— namely,  1 9  0  in  a  million  ;  but  if  we  examine  the  table 
we  shall  find  much  greater  quantities.  Take,  for  example, 
the  pit  of  a  theatre;  we  have,  by  subtracting  20*74 
from  20 '9 9 9,  a  difference  o'f  2590  in  a  million,  or  14 
times  more.  And  so  on  we  may  descend  to  the  lowest 
in  the  series,  where  we  have  17 "2,  which,  taken  from 
20-999,  leaves  3-799,  or  37,990  in  a  million,  or  200  times 
more  than  the  first  example. 

Carbonic  Acid. — The  amount-  of  carbonic  acid  in  the  carbonic 
air  varies  according  to  Boussingault^  Farsky,  Henneberg,  ^"'^' 
Pettenkofer,  and  Cleasson,  in  different  parts  of  the  world 
from  -279  to  '060  per  cent.  It  has  been  experimentally 
shown  that  its  quantity  in  the  air  :  (1)  is  greater  in  the 
night  than  by  day  on  land,  due  doubtless  to  the  large 
amount  evolved  by  vegetation  during  the  hours  of  dark- 
ness; (2)  is  slightly  increased  towards  noon  and  after  rain  ; 
(3)  is  greater  in  the  air  collected  above  the  ocean  by  day 
(•05  per  cent)  than  by  night  (-03  per  cent).     M,  Mene^ 

^  Comptes  Rendus,  Ivii.  155. 


228 


THE    PUEITY    OF    AIE 


has  found  that  the  proportion  of  carlDonic  acid  in  the  air 
varies  at  different  seasons,  being  constant  in  December 
and  January,  increasing  in  February,  ]\Iarch,  April,  and 
May,  and  decreasing  from  June  to  August,  increasing 
again  from  September  to  November,  and  attaining  its 
maximum  for  the  whole  year  in  October.  Saussure  dis- 
covered that  the  carbonic  acid  of  mountain  air  is  in  larger 
amount  than  in  that  of  plains.  The  remarkable  uniformity 
and  constancy  in  the  amount  of  carbonic  acid  contained  in 
the  air  of  our  parks  and  fields  in  the  neighbourhood  of 
cities,  notwithstanding  the  universal  pollution  of  the  air 
rhat  is  unceasingly  proceeding,  shows  the  existence  of 
tecuperative  forces  in  nature  of  the  greatest  magnitude. 

The  observations  made  by  M.  Marie-Davy  at  the 
Montsouris  ObserA^atory,  which  is  situated  at  the  junction 
of  Paris  with  the  country,  seem  to  furnish,  as  a  rule,  much 
lower  results  than  were  obtained  by  Mr.  Dixon  in,  and  in 
the  \acinity  of,  Glasgow.  "Whilst  the  percentage  ranges 
between  '02  and  '03  at  the  former  station,^  it  somewhat 

■^  In  order  to  render  the  differences  in  the  amount  of  carbonic  acid  in 
the  air  more  apparent,  he  registers  it  as  litres  in  100  cubic  metres  of  air, 
which  can  be  easily  changed  into  percentages  by  placiug  tlie  figure  0 
before  the  iirst  figure  and  removing  the  decimal  point  to  a  position  in  front 
of  that  0,  e.g. 

Monthly  mean  29 '7  =  "0297  per  cent. 

rarh  of  Montsouris. 

Average  of  nine  years  observations  involving  more  than  3000  analyses. 

Annucd. 

.  28-6 
.  29-0 
.  29-6 
.     29-3 


1877    . 

.     28-4 

1882      . 

1878     . 

.     34-5 

1S83      . 

1879     . 

.     32-9 

1884      . 

1880     . 

.     27-0 

1885      . 

1881     . 

.     27-7 

Annual  mean,  29 '6. 

Monthly. 

January 

.     30-4 

July      . 

February 

.     29-7 

August 

March . 

.     29-6 

September 

April   . 

.     29-8 

October 

May     . 

.     29-9 

November 

Juna 

.     30-3 

December 

Monthly  mean,  29 '7. 


THE    PUEITY    OF    AIR  229 

exceeds  "03  at  the  latter  stations.  Nor  is  this  divergence 
wholly  due  to  differences  in  the  quality  of  the  air  around 
Paris  and  around  Glasgow.  There  is  a  very  strong  pro- 
bability, ahnost  amounting  to  certainty,  that  it  is  partly 
owing  to  the  greater  speed  at  which  the  air  is  passed 
through  the  chemical  reagent  at  Montsouris  than  at 
Glasgow.  JVI.  Marie-Davy  transmitted  air  through  his 
aspirator  at  the  rate  of  about  10  cubic  feet  per  hour, 
whilst  Mr.  Dixon  sent  1  cubic  foot  of  air  through  his 
absorbing  solution  in  the  same  space  of  time.  Chemical 
action  consumes  a  certain  definite  time,  and  if  we  hurry 
air  through  a  chemical  solution,  intended  to  withdraw 
from  it  any  body  wliich  it  contains,  too  rapidly,  the  air 
is  not  thorouglily  deprived  of  the  same. 

Eecent  experimenters  have  found  a  larger  amount  of 
carbonic  acid  on  the  summits  of  high  mountains  than  on 
their  sides  at  a  lower  elevation.  ( Vide  following  Table.) 
The  observations  made  by  M.  G.  Tissandier  in  his  late 
ascent  in  the  balloon  named  the  "  Zenith,"  are  confirmatory 
of  their  results,  for  he  found  at  an  altitude  of  from  800 
to  890  metres  that  the  amount  of  carbonic  acid  in  the 
air  was  '024  per  cent,  and  at  1000  metres  "03  per 
cent.^  Although  many  explanations  of  what  must,  I 
suppose,  be  admitted  as  a  fact  have  been  attempted,  not 
one  has  as  yet  been  offered  which  is  altogether  satisfactory. 

As  in  the  case  of  the  amount  of  oxygen,  so  in  that  of 
the  quantity  of  carbonic  acid,  in  pure  or  moderately 
pure  air,  there  is  a  remarkable  absence  of  discrepancy  in 
the  analyses,  made  by  different  chemists  by  dissimilar 
processes,  of  air  taken  under  similar  conditions  in  various 
parts  of  the  world. 

^  Gomptcs  Rcnclus,  April  12,  1875. 


230 


THE    PURITY    OF   AIR 


Mean  of  18  analyses  on  Lake  Geneva,  by  Sanssure^ 
Air  of  Madrid   outside   tile  walls.     Mean  of  12  analyses 

by  Luna^       ...... 

Air  of  Madrid   inside   tbe  walls.      Mean  of  12    analyses 

by  Luna        ...... 

Air  of  Municb,  by  Pettenkofer  ^  . 

Air  of  summit  of  Mont  Blanc,  by  Frankland  * 

Air  over  Irish  Sea,  July  and  August  (Dr.  Thorpe) 

Air  in  Brazil  (April  and  May) 

Hills  above  3000  feet  ."        .    (A.  Smith) 

„     between  2000  and  3000  feet  „ 

„  „         1000  and  2000  feet  „ 

„     below  1000  feet  .  .  „       . 

At  the  bottom  of  the  same  hills   . 
On  hills  in  Scotland  from  1000  to  4406  feet 
In  the  streets  of  London  (summer) 
In  the  London  parks  and  open  places    . 
On  the  Thames  at  London  .... 
In  the  streets  of  Glasgow  (E.  M.  Dixon).      Mean  of 

results  for  May  and  June  1877 
Air  of  S.W.  suburbs  of  Leicester  (Weaver) 


Per  cent. 
•0439 

•045 

•051 

•050 

•060 

•030 

•032 

•0336 

•0332 

•0334 

•0337 

■0341 

•0332 

•0380 

•0301 

•0343 

•0304 
•0460 


1  Ann.  de  Chem.  ct  de  Phys.,  vol.  xliv.  1830. 

2  Estudios  quimicos  sobre  et  aire  atmosferico  de  Madrid,  1860. 

^  HandworterMich  der  Chemie — Yentilation. 

"  Ou  the  Air  of  Mont  Blanc  ; "  Jounuil  of  Chemical  Society,  1861. 

^  Journal  of  Chemical  Society,  1867. 


PAET    I 

DIFFERENT    KINDS    OF    IMPUPJTIES 


The  air  is  deteriorated  in  quality  and  defiled  by —  Different 

1.  Eespiration  ^  and  Transpiration.  whereby  air 

2.  Combustion.  isdeterio- 

rated  in 

3.  Putrefactive  processes,  sewage  emanations,  and  excre- quality  and 

mental  filth. 

4.  Gases,  vapours,  and  suspended  metallic,  mineral,  and 

vegetable   matters  given  off  by  trades  and   manu- 
factories. 

5.  Poisons  of  unknown  nature  evolved  by  damp  and  filthy 

soil. 

^  The  changes  that  are  found  to  have  taken  place  in  pure  air  that  has 
been  respired  are  roughly  the  following  : — 

(1)  100  parts  of  air  contain  only  13,  instead  of  about  21,  parts  of  oxy- 
gen, the  missing  8  parts  having  been  withdrawn  by  the  blood  corpuscles 
in  the  lungs. 

(2)  The  "03  or  -04  part  per  cent  of  carbonic  acid  is  increased  to  between 
4  and  5  per  cent. 

•    (3)  An  increase   of  watery  vapour   is   noted,  which  is   loaded   with 
organic  matter. 


CHAPTEE    XVIII 


ORGANIC   MATTEE 


Organic 
matter. 


Animal. 


All  air  contains  some  organic  matter,  which  may  be  of 
different  kinds.  It  has  been  divided  into  («)  the  whole- 
some, (h)  the  neutral,  (c)  the  putrid,  and  (d)  the  organized 
=  dangerous  form. 

I  apprehend  that,  in  designating  any  particular  kind 
of  organic  matter  as  wholesome,  it  is  not  intended  to  con- 
vey the  idea  that  the  presence  in  air  of  this  variety  is 
conducive  to  health,  but  rather  that  it  does  not  influence 
health  in  one  way  or  the  other.  It  would  be  as  well 
perhaps  to  combine  the  "  wholesome  "  and  "  neutral "  into 
one  class,  thus  making  only  three  varieties.  It  may  be 
said  at  the  outset  that  it  is  quite  impossible  by  chemical 
means  to  distinguish  one  variety  of  organic  matter  from 
another. 

Organic  matter  may  be  of  an  animal  or  of  a  vegetable 
nature,  but  the  sum  and  substance  of  all  the  most  recent 
observations  on  air  is,  that  the  bodies,  the  presence  of 
which  creates  the  difference  between  good  or  healthful  air 
and  bad  or  deleterious  air,  are  mainly  of  a  nitrogenous 
organic  character. 

Animal  organic  matter  is  thrown  off  from  the  lungs 
in  respiration,  and  from  the  skin  by  transpiration,  in  a 
state  of  invisible  vapour  and  of  epithelial  dust.  In  1870 
Dr.  Eansome  read  a  paper  -^  "  On   the  Organic  Matter  of 

^  Proc,  of  Manchester  Philosph.  Socy.,  February  22,  1870. 


ORGANIC    MATTER 


n  o  o 


Human  Breath  in  Health  and  Disease,"  in  which  he  stated 
that  the  vapour  of  human  breath  in  adults  in  a  state  of 
health,  if  condensed  in  a  large  glass  flask,  surrounded  by 
ice  and  salt,  and  examined  by  the  Wanklyn,  Chapman, 
and  Smith  process,  yielded  about  3  grains  of  organic 
matter  in  10  ounces  of  the  condensed  fluid,  a  quantity 
sufficient  to  make  the  fluid  highly  decomposable,  and 
ready  to  foster  the  growth  of  those  lowly  organisms  that 
we  believe  to  be  the  intimate  companions  of  the  morbific 
ferments. 

This  animal  organic  matter  decomposes  and  gives  off 
various  volatile  nitrogenous  compounds,  which,  although 
they  may  not  themselves  produce  disease,  undoubtedly 
lessen  the  power  of  the  body  to  resist  its  attack.  More- 
over, putrefying  animal  matter  is  a  favourite  pasture  for 
the  development  and  dissemination  of  the  animal  poisons. 
It  would  seem  to  exert  a  distinctly  poisonous  action  on 
one  at  least  of  the  lower  animals,  if  we  are  to  accept  the 
experience  of  Dr.  Hammond,  who  placed  a  mouse  under  a 
bell  glass,  taking  care  to  supply  it  with  plenty  of  oxygen, 
and  removing  all  carbonic  acid  and  watery  vapour,  per- 
mitting the  organic  matter  to  remain.  The  mouse  died 
in  45  minutes. 

Excremental  filth,  in  a  condition  of  impalpable  powder, 
is  often  present  in  the  air,  and  is  the  most  disgusting  of 
all  the  impurities  to  which  man  is  exposed.  As  many 
diseases  pro^mgate  themselves  by  eliminating  their  poisons 
through  the  medium  of  the  exhalations  and  excretions  of 
the  body,  air  thus  polluted  is  often  the  bearer  of  the  or- 
ganic poisons  by  which  maladies  are  disseminated. 

Medical  men  and  district  visitors,  who  enter  the  dwell- 
ings of  the  poor  in  crowded  courts  and  alleys,  are  perfectly 
familiar  with  the  foetid  emanations  that  abound  in  such 
unwholesome  styes.  The  peculiar  sickening  odour  of  or- 
ganic matter  is  especially  noticed  in  crowds  of  the  great 


234  ORGANIC    MATTER 

unwashed,  and  creates  often,  in  those  unaccustomed  to 
such  smells,  a  feeling  of  faintness,  languor,  and  debility. 

VegetahU  organic  matter,  if  excessive  in  the  air,  is 
associated  with  a  poison  productive  of  ague  and  other 
malarial  affections.^  Whether  or  not  there  exists  any 
causative  relation  between  the  micro-organism  named  the 
bacillus  malarias  and  these  diseases,  is  still  a  moot  point. 

The  quantity  of  the  nitrogenous  material  (ammonia 
and  albuminoid  ammonia)  found  in  air  varies,  of  course, 
and  is  a  measure  of  its  impurity,  be  it  furnished  by 
animal  and  vegetable  decomposition,  or  by  soot  and  im- 
perfectly consumed  organic  impurities  proceeding  from 
manufactories.  Dr.  Angus  Smith  discovered  "066  milli- 
gramme of  ammonia,  and  '190  milligramme  of  albuminoid 
ammonia,  in  each  cubic  metre  of  air  in  a  bedroom  at  9 
P.M.,  and  "095  milligramme  of  the  former,  and  '334  milli- 
gramme of  the  latter,  per  cubic  metre,  in  the  same  room 
on  the  following  morning  at  7  A.M."  Mr.  Moss  ^  whilst 
finding  as  a  mean  of  eight  observations  "093  milligramme 
of  ammonia  and  '088,  or  roughly  "09  milligramme  of 
albuminoid  ammonia,  in  each  cubic  metre  of  the  air  of 
Portsmouth,  estimated  the  proportions  present  at  the  same 
time  in  the  Portsmouth  Hospital,  in  the  officers'  quarters, 
etc.     (  Vide  Table.) 

Ammonia  generally  occurs  in  the  air  as  a  salt,  such 
as  the  carbonate,  chloride,  nitrate  or  nitrite,  derived  from 
decomposing  animal  matters,  such  as  manure,  sewage,  effete 
matters  from  the  lungs  and  skins  of  men  and  other  animals, 
from  soot  and  manufacturing  products. 

Some  express  the  amount  of  the  ammonia,  and  the 

*  The  answer  of  Dr.  C.  F.  Oldham  to  the  query  which  forms  the  title 
of  his  work,  What  is  Malaria  ?  namely  that  "  Malaria  is  chill,"  and  that 
ague  and  other  malarial  diseases  are  not  produced  by  a  specific  poison,  is 
not  accepted  by  the  medical  profession. 

^  "  Air  and  Eain."  ^  Lancet, 'Novemhev  2,  1872. 


ORGANIC    MATTER  235 

ammonia  derived  from  albuminoid  ammonia,  which  they 
detect  in  air,  in  terms  of  nitrogen,  by  multiplying  by  14, 
and  dividing  the  result  by  17.  The  nitrogen  from  both 
kinds  of  ammonia  being  added  together,  is  recorded  as  the 
total  nitrogenous  matter  in  the  sample. 

The  old  methods  of  estimating  ammonia,  in  vogue 
before  the  discovery  of  the  Nessler  test,  yielded  most  con- 
tradictory evidence.  The  invention  of  this  re-agent,  which 
can  be  worked  with  marvellous  delicacy  and  precision, 
has  inaugurated  a  new  era  in  air  and  water  analysis.  The 
following  observations  have  all  been  made  by  its  assistance 
in  different  ways,  which  will  be  described,  in  connection 
with  the  names  of  the  analysts,  in  the  chapter  on  "  The 
Chemical  Examination  of  Air,"  page  310  ; — 


236 


ORGANIC    MATTER 


Air-Washings. 

By  Dr.  Angus  Smith,  Mr.  W.  A.  Moss,  and 
Dr.  C.  B.  Fox. 


Milligramme  in  One 

Sample  of  Air. 

Time  and  Weather. 

Cubic  Metre  of  Air. 

Ammonia. 

Albuminoid 
Ammonia. 

In  Manchester, 

Laboratory  Office,  10  a.m. 

.... 

•106 

•266 

,,                   ,,           4  P.M. 

•133 

•293 

Gas-room,  10  a.m, 

•130 

•213 

,,       ,,         4  p.m. 

•190 

•427 

Yard   behind   laboratory 

Fine,"  Oct.  28,  1869  . 
Freezing,  snow  on  the 

•095 

•095 

ground,  Dec.  28     . 

•106 

•356 

)j           J »               )? 

Damp,  Jan.  13,  1870 

•059 

•213 

Fine,  Jan  25,  1870    . 

•190 

•316 

5  )                   J5                           :  J 

Foggy,  Jan.  26,  1870 

•142 

•221 

Street,  open 

Raining,   and   strong 

Average 
Bedroom — Average  of     . 

wind,  Dec, 

•071 

•261 

■122 

■266 

•101 

•238 

Midden — Average  of 

•336 

•415 

In  London. 

Average 

•061 

•150 

Air  of  the  Underground 

Nov.  11  and  12  (morn- 

Railway      (Metropoli- 

ing) 

•109 

•457 

tan),  1869 

Chelsea  (three  places) 

Nov.  4,  windy  . 

•045 

■110 

Brompton  ,,         ,, 

Nov.  4,  windy,  and  a 

shower  of  rain 

•047 

■128 

In  Glasgow, 

Average  . 

•078 

•304 

Shore,  Innellan,  Firth  of 

March     s",      N.N.K 

Clyde 

wind 

•052 

•137 

ORGANIC    MATTER 


237 


Air-Washings — Continued. 


Milligramme  in  O^e 

Sample  of  Air. 

Remarks. 

Cubic  Metre  of  Air. 

Ammonia. 

Albuminoid 
Ammonia. 

In  Portsmouth. 

Mean   of   eight   observa- 

Air obtained  at  eleva- 

tions at  different  times 

tion  of  20  feet 

•093 

•088 

in  open  air 

Rooms      (Officers'     Quar- 

•436 

•462 

ters) 

No.  5  Ward  of  Hospital 

•428 

1-307 

>j                J) 

• 

•855 

1-018 

No.  7.    „ 

•520 

-753 

Variola  Ward 
Rubeola    Ward    (cliil-     - 
dren         .         .         . 

Both  were  freely  ven-  \ 
tilated,andinboth  < 
disinfectants  were  I 

•309 
•226 

-416 
-197 

freely  used    .          ) 

Respired  air  in  health- 

•218 

•545 

)J                                     5) 

. 

•122 

•169 

3)                                    )  ) 

•112 

•099 

)J                                    )) 

•144 

•177 

In  Essex. 

Air  on  banks  of  Thames 

Wind    flowing    from 

after      passing      over 

river  to  shore 

•03 

•10 

marshes 

Air  of  sitting-room 

Occupied  by  one  per- 
son for  several  hours. 
Good  fire.      Venti- 
lation by  draughts 
underneath  door 
and  windows,  which 

open  to  ground 

•066 

•265 

Air    of    bedroom,     after 

No  ventilation  of  any 

being  occupied  by  three 

kind 

•264 

1-367 

persons  for  nine  hours, 

at  7  A.M. 

Pure  air  of  meadow 

. 

•066 

■044 

By  Mr.  W. 
A.  Moss. 


By  C.  B. 
Fox,  M.D. 


1  The  amount  of  impurity  found  in  the  air  of  this  ward  gives,  I  should 
imagine,  a  fair  example  of  the  state  of  a  fully  occupied  ward  under  ordinary 
conditions. — AV.  A.  M. 

2  These  analyses  show  a  considerable  variation  in  purity,  even  in  the 
same  individual.  It  appears  probable  that  a  far  larger  amount  of  organic 
matter  passes  into  the  air  from  the  skin  than  from  the  lungs. 


238  OEGANIC    MATTEK 

Theobserva-  The  observatioiis  tliat  were  conducted  some  years  ago 
Glasgow,  on  the  air  of  several  parts  of  the  city  of  Glasgow  by  E. 
M.  Dixon,  B.Sc,  and  W.  J.  Dunnachie,  show,  as  regards 
its  organic  impurities,  two  maxima — one  towards  the  end 
of  August,  due  to  increased  temperature  which  is  the 
principal  factor  concerned  in  late  summer  in  the  greater 
activity  of  all  putrefactive  changes  in  nitrogenized  material, 
and  the  other  in  winter.  The  winter  maximum  simply 
indicated  the  amount  of  tangible  floating  soot  in  the  air, 
for  no  measures  were  taken  for  excluding  from  the 
absorbing  solutions  the  particles  of  soot  which  in  the  air 
of  such  a  smoky  city  as  Glasgow  are  particularly  abundant 
in  the  foggy  days  of  winter  when  there  is  an  extra  con- 
sumption of  coals.  If  a  small  particle  of  soot  is  shaken 
violently  with  some  ammonia-free  distilled  water,  and  the 
mixture  is  analyzed  by  the  Wanklyn,  Chapman,  and 
Smith  process  of  water  analysis,  it  will  be  found  very 
difficult  to  extract  all  the  ammonia.  Particles  of  soot 
contain,  in  addition  to  a  great  deal  of  ammonia,  imperfectly 
consumed  organic  matter  derived  from  fires  and  manu- 
factories, which,  when  decomposed  by  boiling  with  caustic 
soda  and  permanganate  of  potassium,  yield  ammonia 
freely. 

The  proportion  of  organic  matter  in  air  is  also  estimated 
by  making  examinations  of  the  amount  contained  in  that 
Eain.  great  air-washer,  rain.  Eain  dissipates  the  deleterious 
gases  which  accumulate  and  float  over  towns  and  cities. 
It  brings  down  from  the  higher  regions  of  the  atmosphere 
a  more  salubrious  air,  and  by  the  flushing  of  drains  and 
cleansing  of  the  surface  of  the  country,  aids  in  the  preven- 
tion of  the  contamination  of  the  air  by  the  exhalations  of 
animals,  and  by  the  decomposition  of  animal  and  vegetable 
matter  which  is  incessantly  proceeding.  The  following 
analyses,  made  by  Dr.  Angus  Smith,  evince  very  important 
differences  : — 


ORGANIC    MATTER  239 


Eain  Waters  collected  during  1869. 

Albuminoid 

Ammonia. 

Part  per 

Million =JHilligr. 

per  Litre. 

Darmstadt,  February         .  .  .  .  .  .  "30 

Do.         during  a  thunderstorm,  May  26        .  .  "075 

Zwingenburg,  near  Heidelberg,  July  .  .  .  '15 

Heidelberg,  June  15 -087 

Tyree,  Mayi '30 

Kelly,  Wemyss  Bay,  south-west  wind,  June  2  to  15   .  "075 

St.  Helens,  west  wind,  February  18  to  March  11        .  "15 

Do.       April  23 -20 

Manchester,  during  a  thunderstorm.      Rain  had  fallen 

heavily  just  before.     Collected  about  2 

feet  from  the  ground,  September  10     .  "079 

Do.  2  feet  from  the  ground, behind  the  Literary 

and  Philosophical  Society,  September  .  '25 

The  close  agreement  in  chemical  composition  as  re- 
gards the  amount  of  organic  matter  of  pure  air,  and  of  rain 
that  falls  through  country  air  far  away  from  animal  and 
vegetable  vitiating  agencies,  and  of  well  water  of  aver- 
age cleanliness,  cannot  but  attract  the  attention  of  the 
analytical  student  of  nature.  About  "08  of  one  part  per 
million  appears  to  be  the  mean  amount  of  albuminoid 
ammonia  contained  in  air,  in  rain,  and  well  water  that 
has  not  received  any  extra  impurities  from  organic  life. 
The  study  of  the  compensatory  forces  of  nature,  as 
manifested  in  that  universal  tendency  to  a  restoration 
to  a  state  of  equilibrium  of  everything  that  has  to  some 
extent  departed  from  it,  may  well  occupy  the  minds  of 
those  whose  pursuits  lead  them  to  the  contemplation 
of  the  laws  by  which  this  world  is  governed  in  special 
relation  to  the  life  and  health  of  its  inhabitants. 

^  A  large  kelp  work  exists  on  the  island. 


CHAPTEE    XIX 

OXIDES    OF    CAEBON 

Carbonic  A.  Ccirhonic  Acid. — The  discomfort  wliich  we  experience 
in  badly  ventilated  rooms  was  formerly  considered  to 
be  occasioned  by  the  production  of  carbonic  acid.  We 
now  know  that  it  is  caused  mainly  by  organic  matter, 
and  that  an  excess  of  carbonic  acid  can  be  borne  without 
ill  effects,  if  the  air  be  free  from  deleterious  gases  and  an 
excess  of  organic  impurity.  Still  the  amount  of  carbonic 
acid  is,  as  a  rule,  a  measure  of  other  accompanying  im- 
purities in  the  air,  for  it  is  almost  always  found  in  bad 
company, 

A  confidence  in  our  powers  of  measuring  very 
accurately  the  minutest  quantities  of  carbonic  acid  is 
established  by  the  harmony  that  has  been  already 
shown  to  exist  on  page  230,  between  the  results  ob- 
tained by  analysts  on  air  of  varying  degrees  of  purity, 
which  is  still  further  increased  by  our  study  of  such 
an  interesting  series  of  observations  of  air,  of  various 
degrees  of  impurity,  as  are  collected  together  in  the  follow - 
insc  Table : — 


OXIDES    OF    CARBON" 


241 


Carbonic  Acid  in   Public  and  Private    Buildings  in 
Leicester,  by  E.  Weaver,  C.E.,  F.C.S> 


Nature  of  Workroom  or  Building. 


Carbonic  acid 
per  100  of  air. 


1.  Boot  and  shoe  finisher 

2.  Framework  knitter    . 

3.  Ditto  ditto 

4.  Boot  and  shoe  finisher 

5.  Needlemaker 

6.  Tailor's  workshop 

7.  Boot  and  shoe  finislier 

8.  Tailor's  workshop 

9.  Elastic  web  manufacturer 

10.  Fancy  hosier . 

11.  Boot  and  shoe  riveter 

12.  Riveting-room  of  boot  manufacturer 

13.  National  school :  Science  class-room 

14.  Ditto  Boys'  day-room 

15.  Ditto  Girls'  day-room 

16.  Ditto  Boys'  day-room 

17.  Ditto  Girls'  day-room 

18.  Police  Court:  The  Mayors' parlour 

19.  Ditto         The  Town  Hall 

20.  Private  house  :  sitting-room 

21.  Worsted  spinner's  preparing-room 

22.  Ditto  doubling-room 

23.  Town  Hall  during  Quarter  Sessions 

24.  Prisoners'  cell  in  police  station 

25.  Police  station  :  Sergeant's  office 

26.  Prisoners'  cell  at  Town  Hall 

27.  Spring  Assizes  :  Crown  Court ;  body  of  hall 

28.  Ditto  Ditto  gallery 

29.  Ditto  ISTisi  Prius  Court ;  body  of  hall 

30.  Ditto  Ditto  gallery 

31.  Newspaper  office  ;  Compositors'  room 

32.  Ditto  Machine  room 

33.  Ditto  Compositors'  room 

34.  Private  house  :  One  foot  from  floor  of  bedroom 

35.  Ditto         One  foot  from  ceiling  of  same  room 

36.  Ditto  One  foot  from  floor  of  bedroom 

37.  Ditto  One  foot  from  ceiling  of  same  room 

38.  National  school :  Infants'  room 

39.  Ditto  Girls'  Room 

40.  Private  school  .  .  .  . 

41.  Ditto       ..... 

42.  Elastic  web  manufactory :  The  lower  or  braid  room 

43.  Ditto  The  upper  or  weaving  room 

44.  Public  library  :  Reading-room 


•528 
•532 
•408 
•460 
•287 
•306 
•259 
•217 
•211 
•493 
•172 
■328 
•241 
•116 
•164 
■309 
•204 
•120 
■098 
•304 
•106 
•174 
•153 
•103 
•203 
•081 
•196 
•290 
•134 
•169 
■111 
■123 
•149 
•102 
•150 
•116 
•164 
•154 
•139 
•120 
•121 
•178 
•328 
■206 


1  Lancet,  July  6,  August  3  aud  17,  1872. 
E. 


242 


OXIDES    OF    CAEBON 


Mr.  Weaver  points  out  that  the  condition  of  the  air 
in  the  sitting-room  of  a  private  house,  No.  20,  ilhistrates 
that  of  a  great  number  of  unventilated  dweUings  occupied 
by  mechanics  and  clerks,  where  gas  is  burning.^ 

The  higher  percentage  of  carbonic  acid  in  the  galleries, 
as  shown  by  the  observations  I^os.  27  to  30,  testifies  to 
the  fact  of  its  ascension  with  the  aerial  currents,  and  that 
there  is  no  tendency  towards  accumulation  in  the  lower 
strata  of  air  from  greater  specific  gravity,  as  has  been 
sometimes  stated. 


Carbonic  Acid  in  London,  Manchester,  New  York, 
Cornwall,  Portsmouth,  and  elsewhere. 

By  Drs.  Smith,  and  Bernays,  F.  de  Chaiimont,  and  others. 

Percentage  by 
volume. 


Chancery  Court,   closed   doors,  7    feet  from  ground 
March  3 

Same,  3  feet  from  ground 

Strand  Theatre,  gallery,  10  p.m. 

Surrey  Theatre,  boxes,  March  7,  1.03  p.m 
„  „  ,,       March  7,  12  p.ii.  . 

Olympic,  11.30  p.m.         .... 
„  11.55  P.M 

Victoria  Theatre,  boxes,  March  24,  10  p.m. 

Haymarket  Theatre,  dress  circle,  March  18,  11.30  p.m 

Queen's  Ward,  St.  Thomas'  Hospital,  3.25  p.m. 

Edwards'    „  „  „  3.30  p.m.  . 


■193 

•203 

•101 

•111 

•218 

•0817 

•1014 

•126 

•0757 

•040 

•052 


^  All  gas  shareholders  should  welcome  the  advent  of  the  electric  light 
for  domestic  purposes  when  they  consider  the  deteriorating  effect  on  the 
air  we  breathe  of  our  present  illuminating  agents. 

Carbonic  acid. 
Argand  eras  burner  ......  ^46 


Petroleum  lamp 
Colza 

Paraffin  candle 
Tallow     . 
Electric  lisrht  . 


•95 

1-00 

1^22 

1-45 

0 


OXIDES    OF    CARBON 


243 


Percentage  by 
volume. 

Pavilion,  10.11  P.M.,  Apriig '152 

City  of  London  Theatre,  pit,  11.15  p.m.,  April  16     .  -252 

Standard  Theatre,  pit,  11  p.m.,  April  16.  .  .  -320 

Stable  for  horses  :  lEcole  Militaire   .  .  .  .  -700 

Crowded  girls'  schoolroom,  seventy  girls  (Pettenkofer)  '72.3 

Mean  amount  in  a  dwelling-house,  during  the  day    .  "068 

In  a  bedroom  at  night  with  closed  windows      .  .  -230 

„  „  ,,  partly  open  .  ,  .  -082 

Sleeping  cabin  of  Dublin  Canal  boat  (Cameron)         .  -95 

Unventilated  barracks  in  London  (Roscoe)         .  .  -124 

Tombs   Prison   (male   department),   New    York    (H. 

Endemann)         .  .  .  .  .  .  .  "147 

Fulton  Market,  New  York  (H.  Endemann)        .  ,  -084 

Manchester  streets,  ordinary  weather        .  ,  .  •0403 

Where  fields  begin -0369 

About  middens       .  .  .  .  .  .  .  '07  74 

In  workshops  .......  -3000 

In  theatres,  worst  part,  as  much  as.  .  .  .  -3200 

In  mines,  largest  amount  found  in  Cornwall     .  .  2'5000 

In  mines,  average  of  339  specimens  ,  .  ,  "7850 


Dr.  F.  de  Chaumont's  estimations  of  the  amount  of 
carbonic  acid  in  the  air  of  barracks,  hospitals,  and  prisons 
are  interesting : — 

Barracks. 


j^LVi  1  ivvroo. 

Per  cent 

Gosport  New  Barracks    ..... 

•06 

Anglesea  Barracks .... 

•14 

Aldershot      ..... 

•049 

Chelsea          ..... 

•07 

Tower  of  London  .... 

•13 

Fort  ELson  (Casemate)     . 

•12 

Fort  Brockhurst  (Casemate) 

•08 

Military  and  Civil  Hospitals. 

Portsmouth  Garrison  Hospital 

•097 

,,            Civil  Infirmary    .... 

•092 

Herbert  Hospital   ...... 

•047 

Hilsea           ,, 

■057 

244 


OXIDES    OF    CAKBON 


Military  and  Civil  Prisons. 

AlclersLot  Military  Prison — Cells    . 
Gosport  „  _  „  „        .  .  . 

Chatham  Convict        ,,  „         .  .  . 

Pentonville  Prison — Cells  (Jebb's  system) 


Per  cent. 
•165 
•13 
•169 
•09 


Dr.  Endemann  obtained  seventeen  samples  of  air  from 
the  public  schools  of  America,  and  found  carbonic  acid 
varying  in  amounts  from  '09  to  "35  parts  in  100  ;  or,  in 
other  words,  from  more  than  twice  to  nearly  nine  times 
the  normal  quantity.  He  gives  the  following  tabular 
results,  obtained  from  some  of  the  public  schools  in  New 
York :— 


Schools. 

Per  cent 

Elm  Street 

•146 

Roosevelt  Street     ..... 

•195 

Thirteenth  Street,  near  Sixth  Aveniie 

•281 

Thirteenth  Street,  near  Seventh  Avenue . 

•213 

Greenwich  Street  ..... 

•176 

Vandewater  Street           .... 

•147 

Madison  Street,  near  Jackson . 

•242 

Dr.  Breiting  made  a  series  of  fourteen  experiments  on 
the  quantity  of  carbonic  acid  contained  in  the  air  of  some 
schoolrooms,  commencing  at  7.45  A.M.,  and  continued  to 
4  P.M.  in  a  room  of  251"61  cubic  metres  capacity,  and 
containing  64  children.  The  amount  of  carbonic  acid 
was  said  to  vary  from  2-21  to  9 '3  6  per  cent  (!). 

Herr  E.  Schulz  found  in  a  clubroom  "37  per  cent,  and 
in  a  schoolroom  an  amount  of  carbonic  acid  varying  from 
•14  to  '35  per  cent. 

Dr.  Snow  has  concluded  from  his  experiments  on 
animals  "  that  5  or  6  per  cent  by  volume  of  carbonic  acid 
cannot  exist  in  the  air  without  danger  of  life,  and  that 
less  than  half  this  amount  will  soon  be  fatal,  when  it  is 
formed  at  the  expense  of  the  oxygen  of  the  air." 


OXIDES    OF    CAEBON  245 

My  own  determinations  of  the  amount  of  carbonic 
acid  in  air  of  different  degrees  of  purity  teacli  no  more 
than  do  the  foregoing  analyses,  so  that  I  will  not  trouble 
the  reader  at  present  with  any  more  tabular  matter. 

The  purest  air — namely,  that  resting  on  the  sea,  and 
on  the  sides  of  the  highest  mountains — is  thus  seen  to 
possess  rather  more  than  "03  per  cent  of  carbonic  acid, 
which  is  often  increased  in  the  streets  of  cities  to  '04,  an 
amount  which  may  be  doubled  in  foggy  weather.  Much 
discussion  has  taken  place  at  various  times  as  to  whether 
carbonic  acid  is  a  positive  poison  or  simply  an  asphyxiating 
gas.  It  has  now  been  pretty  clearly  established  that  this 
gas  is  a  distinct  poison  when  diluted  with  air,  but  that,  in 
a  pure  or  unmixed  state,  as  it  is  sometimes  found  in  a 
beer  vat  or  old  well,  it  extinguishes  life  in  a  mechanical 
manner,  by  immediately  suffocating  any  one  who  may  be 
immersed  in  it. 

The  presence  or  absence  of  injurious  bodies  in  air 
(such  as  hydrogen  sulphide,  methyl  hydride,  hydrogen, 
organic  matter,  sulphurous  acid,  ammonia,  ammonium 
sulphides),  and  the  amount  of  oxygen  it  contains,  must 
not  be  lost  sight  of  in  judging  of  the  effects  of  carbonic 
acid  on  the  human  frame.  It  has  been  a  subject  of 
wonder  that  people  have  been  but  slightly  inconvenienced 
by  an  exposure  to  the  air  of  places  where  brewing  is 
going  on,  or  soda  water  is  being  manufactured,  where, 
indeed,  the  air  contains  perhaps  about  '20  per  cent  of 
carbonic  acid.  In  such  cases  the  gas  diluted  with  air  is 
unmingled  with  unwholesome  accessories  as  organic 
matter,  sulphur  compounds,  etc.  Such  air  in  a  closed 
chamber  will  give  to  any  one  who  exposes  himself  to  it  a 
severe  headache.  We  all,  indeed,  avoid  an  atmosphere 
containing  "10  per  cent  of  carbonic  acid  in  crowded 
rooms.  Animals  can  be  kept  alive  for  a  long  period  in 
an  atmosphere  highly  charged  with  it  if  oxygen  be  added. 


246  OXIDES    OF    CAEBOX 

The  body,  when  exposed  to  air  containmg  a  large  excess  of 
carbonic  acid  ('30  ]Der  cent), suffers  a  reduction  in  the  heart's 
action  and  an  acceleration  of  respiration.  These  effects 
have  been  found  to  be  produced  when  the  influence  of  the 
organic  matter  and  other  foreign  bodies  is  eliminated. 
Continual  Estimates  of  the  enormous  quantities  of  this  gas  that 

the  air.  ^re  clailj  and  hourly  poured  forth  by  our  cities  would  be 
alarming  indeed  were  we  not  consoled  by  the  knowledge 
of  the  rapid  distribution  of  gases  by  diffusion/  which 
tends  to  maintain  a  state  of  equilibrium  in  the  constitu- 
tion of  the  air.  Dr.  Smith  assures  us  that  15,066  tons 
of  carbonic  acid  are  daily  passed  by  the  city  of  Manchester 
into  the  air  that  envelopes  it,^  and  Dr.  F.  de  Chaumont 

■^  The  influence  of  condensed  aqneous  vapour  in  tlie  air  wliicli  interferes 
with  this  diff'usion  is  well  shown  by  the  hourly  experiments  of  Otto  Hehner 
during  a  London  fog.         Percentage  of  Carbonic  Acid  by  Volume. 

•10 

•08 

•09 

•04  obtained  during  the  mo- 
mentary lifting  of  the  fog. 

•07 
It  has  been  declared  by  Dr.  Frankland  and  others  that  if  London  is 
to  be  freed  from  suff"ocating  fogs,  the  importation  of  bituminous  coal  into 
the  metropolis  must  be  foi'bidden,  and  smokeless  coal  and  coke  be 
substituted.  If  that  sweeping  measure  should  ever  be  carried  out,  it 
would  be  necessary  to  make  it  compulsory  that  every  room  should  have  a 
chimney,  as  the  consumption  of  smokeless  fuel  in  the  shape  of  coke,  etc. , 
in  rooms  without  flues  has  produced  so  many  fatal  accidents.  Smoke, 
however,  is  not  the  only  cause  of  fog,  for  Prof.  Dewar  has  shown  that 
aqueous  vapour  has  a  tendency  to  condense  into  mist  in  the  presence  of  a 
mere  trace  of  sulphurous  acid,  which  is  an  unavoidable  j^roduct  of  the 
combustion  of  all  kinds  of  coal  and  coke. 

^  M'Dougal  {Chemical  News,  ix.  30),  under  Roscoe's  direction,  deter- 
mined on  two  different  days  the  amoant  of  carbonic  acid  in  the  air  of 
I^lanchester.  As  a  mean  of  46  analyses,  the  air  from  the  centre  of 
Manchester  was  found  to  contain  •OSQ  per  cent  of  carbonic  acid  (max. 
"056,  min.  •0"28),  whilst  the  air  four  miles  from  the  city  exhibited  as  a 
mean  of  eight  determinations  '04  per  cent.  Hence  Roscoe  concludes  that 
in  open  places  the  influence  of  combustion  and  respiration  processes  is 
completely  neutralized  by  the  movements  of  the  air. 


OXIDES    OF    CARBON  247 

states  that  822,000,000  cubic  feet  of  this  gas  are 
generated  in  London  per  day,  or  more  than  9500  cubic 
feet  every  second.  In  consequence  of  the  possession  of 
most  wonderful  self-purifying  properties,  which  are  partly 
due  to  its  powers  of  oxidation  and  partly  to  the  physical 
changes  that  are  unceasingly  occurring  in  its  condition, 
through  the  agency  of  currents,  storms,  rains,  changes  of 
temperature,  etc.,  the  vast  aerial  sea  maintains  a  uniformity 
of  composition  so  marvellous  as  to  strike  with  awe  the 
student  of  the  mighty  forces  of  nature. 

B.  Carbonic  Oxide,  which  is  a  most  poisonous  gas,  iscartonic 
a  product  of  combustion,  and  is  to  be  found  in  the  air  of 
towns,  where  it  is  so  diluted  as  to  do  but  slight  injury. 

Public  buildings,  churches,  colleges,  schools,  barracks, 
etc.,  are  very  often  heated  by  means  of  coke-burning  iron 
stoves,  some  of  which  are  provided  with  troughs  and  pans 
of  water  to  counteract  the  aridity  of  the  air  which  they 
are  supposed  to  induce. 

In  the  United  States  anthracite  (called  in  Ireland 
"  Kilkenny  coal "  and  in  Scotland  "  blind  coal "),  which 
bears  a  gTeat  resemblance  to  coke,  and  is  equally  objec- 
tionable as  ordinarily  consumed,  is  most  extensively  used. 
Dr  Derby  asserts  ^  that  "  ninety-nine  dwelHng  houses  out 
of  a  hundred  in  Boston  are,  in  whole  or  in  part,  warmed 
by  this  fuel,  burned  in  iron  stoves,  or  in  the  iron  fire-pot 
of  a  furnace,  which  is  but  a  stove  in  another  form." 

]\Iany  people  of  nervous  and  sanguine  temperaments, 
especially  the  plethoric,  most  of  those  indeed  who  are 
sensitive  to  changes  in  atmospheric  states  and  conditions, 
are  affected  injuriously  if  they  remain  for  some  time  in  a 
room  or  ofiice  warmed  by  an  iron  stove  in  which  coke  is 
consumed.  They  experience  a  languor  and  oppression ; 
in  fact,  a  sense  of  malaise,  and  sometunes  a  difficulty 
of  breathing,  slight  dizziness,  confusion  of  ideas,  headache 
^  Anthracite  and  Health. 


248  OXIDES    OF    CAEBON 

accompanied  by  a  feeling  as  if  a  tight  band  encircled  tlie 
forehead  and  temples,  in  one  word,  tlie  symptoms  of 
narcotic  poisoning,  whicli  are  speedily  dissipated  on  re- 
moval to  the  fresh  air. 

Now,  what  poisonous  gases  are  generated  by  the 
combustion  of  coke,  coal,  etc.  ?  Carbonic  oxide,  car- 
bonic acid,  the  carburetted  hydrogen  gases,  and  sulphurous 
acid. 

The  last  named,  which  is  so  abundant  in  the  air  of 
coal  and  gas  burning  towns  ^  (where  it  serves  a  useful 
purpose,  being  a  powerful  disinfectant),  hardly  deserves 
to  be  placed  in  juxtaposition  with  such  deadly  agents  as 
carbonic  oxide  and  carbonic  acid. 

The  light  and  heavy  carburetted  hydrogen  gases  may 
be  excluded  from  our  consideration,  for  they  pass  off  in 
comparatively  minute  quantities  in  an  unconsumed  state. 
As  the  carbonic  acid,  which  is  produced  by  the  lower 
layer  of  burning  matter  forming  the  fire,  rises  through 
the  heated  mass  above,  it  unites  with  more  carbon  and 
becomes  changed  into  carbonic  oxide.  This  latter  gas 
may  sometimes  be  seen  burning  on  the  surface,  and 
yielding  a  pale  blue  flame.  When  it  burns  in  contact 
with  air,  carbonic  acid  is  reproduced.  The  presence  of 
carbonic  oxide  is  a  sign  of  imperfect  combustion.  The 
loss  of  heating  power  when  this  gas  escapes  from  a  stove 
has  been  estimated  at  67  per  cent. 

Carbonic  oxide  is  believed  by  all  to  be  a  most  virulent 
poison,  even  m  the  smallest  quantities.  It  is,  if  quite  pure, 
so  free  from  odour  and  creates  so  little  inconvenience  that, 
when  present  in  the  air,  it  is  apt  to  be  breathed  uncon- 
sciously until  the  effects  of  it  are  felt.  It  is  said  to  be 
evolved  by  the  common  puff  ball  when  burnt,  the  fumes 

^  One  of  the  causes  of  the  clifRculty  -which  is  experienced  in  cultivating 
trees  and  shrubs  in  cities  is  to  be  found  in  the  presence  of  this  acid,  Avhich 
is  highly  destructive  to  certain  kinds  of  plants. 


OXIDES    OF    CARBOX  249 

from  which  have  been  employed  for  centuries  to  narcotize 
bees,  before  taking  the  honey  from  the  hive. 

As  both  carbonic  acid  and  carbonic  oxide  gases  are 
given  off'  in  the  combustion  of  coke,  anthracite,  and  char- 
coal ;  and  as  deleterious  effects  may  be  occasioned  by 
either,  and  especially  by  the  carbonic  oxide,  any  escape 
of  them  into  the  air  we  breathe  is  to  be  carefully  giiarded 
against.  Claude  Bernard  and  M.  Guerard  both  assure 
us  that  a  micdure  of  these  gases  is  more  hurtful  than  cither 
respired  alone. 

"V\'Tien  coke  or  anthracite,  which  do  not  contain  the 
illuminating  gases,  and  which  burn  without  flame  and 
smoke,  are  used  in  our  fire-grates,  we  can  generally 
perceive  an  odour  of  sulphurous  acid  on  the  addition  of 
fresh  fuel,  by  placing  the  face  close  to  the  mantel-shelf 
If  this  acid,  w^hich  is  detected  by  its  irritating  fumes, 
escapes  then  into  our  rooms,  it  may  be  fairly  presumed 
that  the  inodorous  gases,  carbonic  oxide  and  carbonic 
acid,  which  are  simultaneously  developed,  are  associated 
with  it. 

Some  may  inquire,  "  Is  it  then  uuadvisable  to  burn  coke  as  a 
coke  in  open  fire-grates  ?"  I  will  answer  this  question  ^'^'^^" 
by  narrating  an  incident  that  once  came  under  my 
notice.  An  extremely  delicate  child,  afflicted  with  a 
pulmonary  affection,  was  ordered,  during  the  prevalence 
of  the  easterly  winds,  to  be  confined  to  a  suite  of  rooms, 
all  maintained  at  one  temperature,  during  both  day  and 
night,  by  coal  fires  in  open  fire-grates.  As  coals  were 
very  expensive,  the  mother  after  a  time  adoj)ted  the 
economical  measure  of  burning  coke.  On  entering  the 
sitting-room,  after  the  introduction  of  the  coke,  to  "sisit 
the  little  patient,  I  experienced  a  sense  of  general 
oppression,  of  weight  about  the  head,  and  a  difficulty  in 
lireathing  aii"  which  seemed  to  have  lost  all  freshness. 
The  child  was  suffering  from  the  symptoms  of  narcotic 


250  OXIDES    OF    CARBOISr 

poisoning.  She  complained  of  great  lassitude  and  of  "  a 
feeling  as  if  a  band  was  tightly  bound  around  the  fore- 
head."     The  rooms  were  not  again  warmed  by  this  fuel. 

It  is  to  be  observed  that  those  who  are  unaccustomed 
to  remain  in  rooms  warmed  by  iron  coke-burning  stoves 
are  more  liable  to  be  unpleasantly  affected  than  those 
who  are  frequently  near  them.  There  is  a  certain 
tolerance  of  the  poison  of  carbonic  oxide  acquired  in 
time  by  those  who  habitually  breathe  it  in  small  amounts, 
such  as  is  seen  in  the  case  of  arsenic,  opium,  etc.  With 
respect  to  the  formation  of  carbonic  oxide  htemoglobulin 
in  the  blood — a  substance  possessing  a  characteristic 
spectrum — I  must  refer  to  my  paper  on  Coke  written 
some  years  ago."^ 

Americans  apj)ear  to  be  fully  alive  to  the  danger  of 
the  poisoning  of  the  air  they  breathe  with  carbon  mon- 
oxide, and  now  employ  wrought -iron  stoves,  which  are 
but  slightly,  if  at  all,  permeable  to  gases.  They  are 
formed  of  plates  riveted  together  as  tightly  as  those  of  a 
steam  boiler,  so  that  the  stove  is  practically  of  one  piece. 
Stoves  constructed  of  Eussian  sheet -iron  (rolled  iron 
covered  with  a  silicious  glaze)  have  also  been  employed. 
The  Germans  appear  to  be  only  partially  aware  of  the 
injury  attendant  on  the  use  of  porous  stoves."  As  the 
majority  of  their  earthenware  stoves  are  covered  with  a 
silicious  glaze,  they  suffer  rather  from  the  dryness  of  the 
air  which  they  occasion  than  from  the  escape  of  poisonous 
gases. 

The  English  seem  perfectly  insensible  at  present  to 
this  danger  to  health,  although  it  has  been  pointed  out 
by  myself^  and  others  for  years, 

^  "Coke  as  a  Fuel,  in  Relation  to  Hj'giene,"  iu  Disease  Prevention. 
"   Vide  Haller's  "Die  Liiftimg  und  Envarmiiug  der  Kinderstube  und 
des  Kranken  Zimmers." 
3  Op.  cit. 


OXIDES    OF    CARBON  251 

The  reader  may  imagine  that,  as  stoves  are  furnished 
with  flues,  every  provision  is  made  for  tlie  removal  of  all  the 
products  of  combustion  into  the  outer  air.  Unfortunately 
these  poisonous  oxides  of  carbon  do  not  all  pass  away  by 
this  outlet,  but  enter  the  rooms  which  the  stove  is  designed 
to  warm  in  three  ways ;  (a)  through  the  iron ;  (&)  at  the 
junctions  of  the  separate  pieces  of  which  a  stove  is  made  ; 
and  (c)  in  consequence  of  downward  currents  of  air. 

The  second  and  third  modes  of  exit  are  readily 
intelligible,  but  the  first  requires  some  explanation. 
MM.  St.  Claire  Deville  and  Troost  have  discovered  that 
iron  and  several  other  metals  permit,  when  heated,  the 
passage  through  them  of  the  gases  of  combustion.  They 
write,  "  The  porosity  results  from  the  dilatation  induced 
by  heat  in  the  intermolecular  spaces."  The  researches  of 
Tyndall  on  the  penetration  of  metals  by  gases,  and  of 
Graham  on  the  absorption  of  carbonic  oxide  by  iron, 
corroborate  these  experiments. 

M.  Dumas  has  distinctly  shown  ^  that  a  portion  of  the 
carbonic  acid  evolved  during  combustion  is  changed  by 
heated  iron  into  carbonic  oxide.  It  is  by  virtue  of  the 
absorptive  power  possessed  by  iron  that  this  metal  is 
converted  into  steel.  We  learn  from  Dr.  Derby's  little 
work,  before  alluded  to,  that  so  long  ago  as  1865  Velpeau 
communicated  to  the  French  Academy  some  observations 
of  Dr.  Garret,  as  to  the  unhappy  influences  on  the  health 
which  attend  the  use  of  cast-iron  stoves.  General  Morin 
interested  himself  in  the  matter,  and  asked  INIM.  St.  Claire 
Deville  and  Troost  to  analyze  the  air  encircling  a  heated 
stove. 

These  chemists  found  :  (1)  that  tubes  of  cast  iron  are 
incapable  of  maintaining  a  vacuum  ;2  (2)  that  carbonic 

^  Connotes  Rcnclus,  August  26,  1872. 

2  The  soil  in  which  pipes  containing  illuminating  gas  are  embedded 
has  often  a  powerful  odour  of  it,  and  is  frequently  much  discoloured.     This 


252  OXIDES    OF    CARBON 

oxide,  carbonic  acid,  and  hydrogen  gases  pass  through 
iron,  and  to  a  still  greater  degree  through  cast  iron ;  and 
(3)  that  carbonic  oxide,  absorbed  in  our  stoves  by  the 
internal  surface  of  the  cast  iron,  diffuses  itself  from  the 
external  surface  into  the  atmosphere,  and  that  this  process 
goes  on  continuously.  They  have  besides  determined  the 
quantity  of  the  oxides  of  carbon  present  in  the  air 
surrounding  heated  stoves,  and  the  proportion  of  carbonic 
oxide  which  permeates  through  a  given  surface  of  a  cast- 
iron  stove,  as  well  as  that  which  the  metal  alDsorbs  and 
retains.^  The  passage  of  the  comparatively  harmless  sul- 
phurous acid  through  the  crystalline  structure  of  cast-iron 
stoves  is  often  recognized  by  its  pungent  and  peculiar  smell. 
Wolffhtigel  and  Prof  Ira  Eemsen  have  expressed 
doubts  ^  as  to  the  permeability  of  cast  iron  to  carbonic 
oxide.  The  latter  did  not  find  in  the  air  around  heated 
cast-iron  stoves  more  than  "04  per  cent  of  this  gas.  The 
Vogel-Hempel  (which  seems  the  most  delicate  known) 
method^   of  testing  for  its  presence  does  not  enable  the 

is,  without  doubt,  partly  occasioned  by  loss  through  the  walls  of  the 
pipes  ;  to  guard  against  which,  so  far  as  is  practicable,  gas  companies  test 
their  pipes  by  submitting  them  to  a  powerful  pressure,  and  lay  them  in  a 
concrete,  composed  of  lime,  etc. ,  which  adhering  to  them  forms  a  pi'otectivc 
coating  that  lessens  the  escape. 

^  The  important  experiments  of  these  chemists  are  contained  in  Comx>tcs 
Eendus,  T.  57,  1863,  and  T.  59,  1864. 

^  "  Carbonic  Oxide  as  a  source  of  Danger  to  Health  in  apartments  heated 
by  Cast-iron  Furnaces  or  Stoves,"  in  Ncdional  Board  of  Health  Bulletin, 
June  25,  1881. 

^  The  Professor  prefers  this  method  to  that  of  S.  von  Fodor,  in  which 
the  blood  of  an  animal  exposed  to  carbonic  oxide  is  shaken  -nith  ammonium 
sulphide — a  test  that  reddens  the  blood  if  the  poison  be  present  and  renders 
it  violet  if  not  present.  This  Vogel-Hempel  method  consists  in  allowing 
a  mouse  to  breathe  the  suspected  air,  in  killing  the  animal,  in  removing  a 
little  of  its  blood  and  diluting  it  with  water,  and  in  examining  it  with  a 
spectroscope.  The  two  bands  characteristic  of  pure  blood  are  replaced,  in 
poisoning  by  carbonic  oxide,  by  a  broad  indistinct  shadow,  not  to  be 
j-emoved  by  ammonium  sulphide,  which  causes  the  disappearance  of  the 
bands  of  pure  blood. 


OXIDES    OF    CARBON  253 

chemist  to  detect  a  smaller  quantity.  Carbonic  oxide  prob- 
ably exerts  its  action  in  the  most  minute  doses.  Whatever 
scientific  chemists  may  or  may  not  be  able  to  discover, 
the  fact  remains  that  physicians  occasionally  encounter 
cases  of  poisoning  from  carbonic  oxide  when  coke  is  burnt 
in  open  grates,  and  that  cases  with  identical  symptoms 
occur  when  cast-iron  stoves  are  employed.  ( Vide  cases 
of  poisoning  by  coke  fumes  in  British  Medical  Journal, 
March  6,  1875,  and  in  Lancet  of  February  14,  1883.) 

The  most  pleasant  and  grateful  of  all  the  artificial 
kinds  of  heat  is  obtained  by  the  consumption  of  coal  in 
open  fireplaces,  although  as  at  present  managed  it  is 
exceedingly  wasteful.  The  quality  of  heat  thus  imparted 
is,  according  to  my  experience,  more  conducive  to  health 
than  that  supplied  by  any  other  fuel.  Ventilation  is 
also  promoted  by  open  fire-grates — an  ordinary  fire 
drawing  about  150  cubic  feet  of  air  per  minute.  A 
brightly  burning  fire  is  an  enlivening  object,  and  tends 
much  to  render  home  attractive  by  its  stimulating  influ- 
ence on  the  spirits.  These  beneficial  impressions  on  the 
nervous  system  are  denied  us  by  the  cheerless  stoves. 

Provided  there  is  a  powerful  draught  in  a  fireplace, 
coke  may  generally  be  burnt  in  it,  mixed  in  small  jjropor- 
tions  toith  coed,  without  causing  a  disturbance  of  nervous 
functions.  The  draught  in  a  chimney  can  of  course  be 
easily  increased,  if  it  is  insufficient,  by  either  lengthening 
the  flue  or  diminishing  the  size  of  it  near  the  fire. 


CHAPTER    XX 

PUTREFACTIVE    PROCESSES,  SEWAGE    EMANATIONS,  AND 
EXCREMENTAL    FILTH 

Putrefactive  The  putrefactive  changes  that  occur  in  organic  matter  are 

processes 

always  associated  with  micro-organisms,  and  are  generally 
accompanied  by  the  production  of  gases  and  vapours. 
Warmth  and  moisture  favour,  and  cold  and  dryness  retard, 
these  putrid  decompositions.  "  The  ferments,  so  far  as  we 
know  them,"  writes  Mr.  Simon,^  "  show  no  power  of  active 
diffusion  in  dry  air ;  diffusing  in  it  only  as  they  are 
passively  wafted,  and  then  probably,  if  the  air  be  freely 
open,  not  carrying  their  vitality  far ;  but  as  moisture  is 
their  normal  medium,  currents  of  humid  air  (as  from 
sewers  and  drains)  can  doubtless  lift  them  in  their  full 
effectiveness,  and  if  into  houses  or  confined  exterior 
spaces,  then  with  their  chief  chances  of  remaining 
effective ;  and  ill- ventilated,  low-lying  localities,  if  unclean 
as  regards  the  removal  of  their  refuse,  may  especially  be 
expected  to  have  these  ferments  present  in  their  common 
atmosphere,  as  well  as,  of  course,  teeming  in  their  soil 
and  ground  water,"  Pysemia  may  probably  be  produced 
in  the  form  of  putrid  infection  or  intoxication  by  a  septic 
poison,  which  can  be  isolated  by  processes  destructive  of 
every  living  organism,  and  also  by  a  septic  poison  which 
is  the  product  of  certain  micro-organisms. 

^  Filtli  Diseases,  in  Report  of  Medical  Officer  of  Privy  Council  and 
Local  Government  Board.     New  Series,  No.  II.  1874. 


PUTKEFACTIVE    PEOCESSES  255 

Sewer  gas,  which  is  one  of  the  media  for  the  convey- sewage 
ance  of  the  poisons  of  the  filth  diseases,  includhig*^""""" 
erysipelas,^  has  been  found  on  analysis  to  be  somewhat 
variable  in  composition.  The  examinations  of  different 
analysts  agree  in  noting  a  diminution  of  oxygen  and 
increase  of  carbonic  acid,  with  small  proportions  of 
hydrogen  sulphide,  carburetted  hydrogen,  and  sulphide 
of  ammonium.  The  characteristic  foetid  odour  of  sewer 
gas  is  due  to  some  organic  vapour  of  carbo-ammoniacal 
origin,  the  precise  composition  of  which  has  not  yet  been 
determined.  Sewage  and  cesspool  effluvia  are  well  known 
to  be  injurious  to  the  health  of  animal  and  vegetable  life, 
even  when  mixed  in  small  quantities  with  the  air.  The 
only  forms  of  life  that  thrive  in  air  thus  polluted  are 
certain  of  the  bacteria  and  fungi,  and  other  of  the  scaveng- 
ing families  of  creation. 

As  to  the  fouling  of  the  air  we  breathe  with  excre-Excre- 
mental  filth,  generally  dried  and  wafted  about  as  dust, 
and  its  connection  with  the  spread  of  such  diseases  as 
cholera  and  typhoid  and  other  of  those  loathsome  filth 
diseases,  the  subject  is  too  disgusting  to  treat  of.  I 
would  simply  refer  my  readers  to  two  sources  for  in- 
formation, if  they  require  any : — first,  to  disclosures  of 
Dr.  Stevens  as  to  the  state  of  Over  Darwen,  when  the 
terrible  outbreak  of  fever  occurred  there  in  1874,  where 
the  people  were  living  with  thousands  of  tons  of  ex- 
cremental  filth  stored  amongst  their  dwellings,  exposing 
a  surface  of  many  acres,  continually  poisoning  the  air 
they  breathed,  and  which  enveloped  them ;  secondly,  to 
Mr.  Simon's  Eeport  on  Filth  Diseases,  in  which  he  writes 
of  enteric  fever — "  Of  all  the  diseases  which  are  attribut- 
able to  filth,  this,  as  an  administrative  scandal,  may  be 
proclaimed  as  the  very  type  and  quintessence ;  that 
though    sometimes    by    covert    processes    which    I    will 

1  Sanitary  Record,  June  6,  1879. 


256  PUTEEFACTIVE    PROCESSES 

hereafter  explain,  yet  far  oftener  in  the  most  glaring 
way,  it  apparently  has  an  invariable  source  in  that  which 
of  filth  is  the  filthiest ;  that  apparently  its  infection  runs 
its  course,  as  with  successive  inoculations  from  man  to 
man,  by  instrumentality  of  the  molecules  of  excrement, 
which  man's  filthiness  lets  mingle  in  his  air  and  food  and 
drink." 


CHAPTEE    XXI 

POISONOUS    GASES    AND    INJURIOUS    VAPOUES 

Such  as  hydrochloric  acid  gas  from  alkali  works,  arsenical 
vapours  from  copper -smelting  works,  hydrofluoric  acid 
from  superphosphate  manufactories,  etc.,  injure  animal 
and  vegetable  life,  sometimes  destroying  all  trace  of  the 
latter  for  miles  around.  Then  the  air  is  vitiated  by 
bisulphide  of  carbon  from  indiarubber  works  ;  ^  chlorine, 
sulphurous  and  sulphuric  acids  from  bleaching  works ; 
hydrogen  sulphide  from  chemical  works  where  ammonia 
is  manufactured.  It  is  poisoned  also  by  carbonic  acid, 
carbonic  oxide,  and  hydrogen  sulphide,  from  brickfields 
and  cement  works  ;  by  organic  vapours  from  glue  refiners, 
bone  burners,  slaughter-houses,  etc.,^  and  by  the  fumes  of 
oxide  of  zinc,  producing  "  brassfounders'  ague." 

^  Paper  on  the  injurious  efifects  of  vaponr  of  bisulphide  of  carbon  by 
M.  Poincare  in  ComjJtes  Rendus,  December  2,  1878. 

2  Vide  Dr.  Ballard's  Report  on  Effluvium  Nuisances  in  Sixth  Annual 
Report  of  Local  Government  Board,  containing  the  Supplement  of  the 
Medical  Officer,  1876. 


CHAPTEE    XXII 

SUSPEXDED    AXIMAL,    "\TEGETABLE,    AXD    METALLIC, 
AS    \VELL    AS    MINEKAL    IMPUKITIES 

Are  the  cause  of  an  immense  amount  of  suffering,  the 
non- poisonous  exciting  lung  disease  by  the  irritation 
occasioned. 

After  the  age  of  thirty-five  the  metal  miners  of 
Cornwall  and  Yorkshire  are  liable  to  a  large  mortality 
from  a  disease  commonly  spoken  of  as  "  miners'  rot." 
The  lungs  of  colliers  become  black  with  coal  dust.  The 
evil  is  aggravated  by  the  imperfect  ventilation  and  the 
laborious  ascent  and  descent  by  long  ladders  in  some 
mines.  To  these  causes  nearly  two-thirds  of  the  total 
mortality  amongst  Cornish  miners  can  be  referred.^ 

It  may  be  well  to  enumerate  a  few  of  the  trades 
which  suffer  in  this  way  :^ — 

Potters  suffer  from  the  dust,  and  have  what  is  called 
"  potters'  asthma,"^  or  a  fibrosis  of  lung  with  consolidation. 

Knife-grinders  are  injured  by  the  fine  particles  of  steel, 
and  suffer  from  what  is  called  "  knife -grinders'  rot." 

Millers,  sweeps,  hairdressers,  and  snuff-grinders  are 
liable  to  asthmatic  affections. 

^  Eeport  of  the  Inspectors  of  Mines  in  tlie  United  Kingdom  for  1885. 

^  Vide  Thacki-ah's  work  on  tlie  Effects  of  Arts,  Trades,  and  Professions 
on  Health  mul  Longevity. 

^  It  has  been  publicl}^  declared  that  not  less  than  60  per  cent  of 
■working  potters  die  from  diseases  of  the  lungs. 


SUSPENDED    IMPURITIES  259 

Buttonmakers ;  pin-pointers;  mother-of-pearl  workers; 
cotton,  wool,  and  silk  spinners;^  workers  in  flax  factories  ;^ 
cotton  weavers  ;^  stone  masons ;  grinding  and  millstone 
makers*^  and  glass  makers ;  makers  of  sandpaper  and 
Portland  cement. 

Apart  from  the  very  ob\'ious  injury  to  health  induced 
by  inhaling  dust  of  various  kmds,  the  circumstances 
wliich  attend  the  performance  of  this  injuiious  work  are 
in.  many  cases  higlily  deleterious.  The  hot,  stuffy, 
damp,  rebreathed  air  in  which  large  numbers  of  these 
artisans  are  bathed  during  their  hours  of  labour  is  enough 
in  itself  to  predispose  strongly  to  the  development  of 
disease. 

Some  of  the  metallic  dust  to  which  some  workmen 
are  exposed  is  poisonous. 

Lead  miners,  type-founders,  glazed  card  manufacturers, 
and  lacquerers,  suffer  from  lead  poisoning. 

Manufacturers  of  white  lead  inhale  the  dust  of  tJiis 
metallic  compound.  Plumbers  and  painters  are  very 
often  poisoned  by  this  metal  in  consequence  generally  of 
a  want  of  sufiicient  cleanliness. 

^  Vide  Dr.  Greenliow's  investigations  in  Reports  of  tlie  Medical  Officer  of 
Privy  Council  for  1858-60  and  1861.  Since  the  introduction  of  modern 
machinery  the  evils  have  been  considerably  reduced. 

^  Dr.  Purdon  of  Belfast  writes  : — "  The  Aveavers  suffer  gi-eatly  from 
chest  affections  by  inhaling  the  damp  air,  which  has  an  average  tempera- 
ture of  75°  F.  Many  of  them  being  under  18  years  of  age.  and  being 
obliged  to  stoop  constantly  at  the  looms,  get  contracted  chests,  and  this, 
■with  other  circumstances,  makes  the  death-rate  very  high.  The  rooms  in 
which  the  dressing  of  the  flax  is  carried  on  require  to  be  kept  at  a  tempera- 
ture varying  from  90°  F.  to  125°  F.  No  one  under  IS  j-ears  old  is 
employed  in  these  rooms,  and,  as  it  is  considered  that  their  lives  are 
shortened  several  years,  they  are  paid  very  high  wages." — Lancet,  October 
27,  1877. 

2  Vide  Eeport  of  Dr.  Buchanan's  Inquiry  at  Todmorden,  in  York- 
shire. 

*  Vide  French  millstone-makers'  phthisis,  by  Dr.  T.  B.  Peacock,  in 
£rit.  Med.  Journal,  October  14,  1876. 


260  SUSPENDED  ANIMAL,  VEGETABLE,  METALLIC 

Workers  in  brass  suffer  from  copper  poisoning,  and 
workers  in  mercury  (such  as  silverers  of  mirrors,  quick- 
silver miners),  and  furriers,  from  mercurial  poisoning. 
Workmen  and  women,  who  make  arsenical  wall  papers, 
pigments,  and  artificial  flowers,  suffer  from  inhaling  the 
poisonous  dust  of  some  compound  of  arsenic.^  Many 
persons  who   do  not  gain  a  living  by   paper   or   flower 

Wall  Papers,  making,  but  who  are  unwise  enough  to  adorn  tlie  walls 
of  their  rooms  with  papers  of  gorgeous  hues,  suffer  also, 
and  know  not  what  ails  them. 

Mr.  Kerley  found  that  a  room,  16  feet  square  and  9 
feet  high,  will  have  spread  upon  its  walls,  provided  any 
of  these  arsenical  papers  are  hung,  from  52  grains  to 
more  than  8  ounces  of  poisonous  green  colouring  matter. 
It  is  a  popular  mistake  to  imagine  that  all  green 
papers  are  coloured  by  arsenic,  or  that  papers  which  are 
not  gTeen  never  contain  arsenic,  for  yellow,  blue,  pink, 
mauve,  red,  brown,  olive,  sage  green,  drab,  and  white 
wall  papers  contain  this  metal.  Cobalt  blue  is  composed 
of  10  per  cent  of  arsenic.  Papers  of  the  most  brilliant 
green  and  otlier  colours  can  be  manufactured  which  are 
quite  free  from  arsenic.  This  coloured  powder  being  apt 
to  be  removed  by  trifling  causes,  is,  of  course,  disseminated 
through  the  air,  and  well  merits  the  epithet  of  "  devil's 
dust."  The  researches  of  Fleck  and  Hamberg  show  that 
this  metal  is  evolved  as  arseniuretted  hydrogen,  as  these 
German  chemists  collected  the  gas.  Lead  papers  and 
copper  papers  are  not  fanciful  dangers.  It  seems  that 
clothing  and  furnishing  materials  are  also  not  exempted 
from  the  universal  system  of  poisoning  and  adulteration 

Clothing,  tliat  prevails.  The  above-mentioned  analyst  estimated 
the  presence  of  5^  ounces  of  aceto-arsenite  of  copper  or 
"  Paris   green "  in  a  green   tarletan    dress    of    16    yards. 

1   Vide  Report  on  the  Manufacture  and  Applications  of  Arsenical  Green, 
by  Dr.  Guy,  in  Fifth  Eeport  of  Medical  Officer  of  Privy  Council,  1S6-2. 


AND    MINEKAL    IMPURITIES  261 

Every  sample  of  tarletan  examined  contained  it ;  the 
higher  priced  qualities  of  this  material  possessing  more 
poison  than  the  cheaper  varieties.  Some  kinds  of  muslin 
are  also  coloured  with  this  poisonous  material.  It  has 
recently  been  discovered  that  the  bright  greens  of  certain 
furnishing  materials,  such  as  chintz  curtains  and  linings,  Furnishing 
consist  of  the  poisonous  compounds — arsenate  of  iron  and 
chromium.  Mr.  Foster,  of  the  Middlesex  Hospital,  who 
has  drawn  public  attention  to  this  matter,^  found  in  each 
square  yard  of  bedroom  chintz  the  metal  arsenic,  in  the 
form  of  an  arsenate,  equal  to  45j1q  grains  of  white 
arsenic,  and  in  each  square  yard  of  the  chintz  lining 
20y^  grains  of  this  deadly  poison.  On  estimating  the 
number  of  square  yards  of  chintz  and  lining  in  the 
bedroom  of  a  gentleman  who  had  suffered  for  some  time 
from  nausea  and  nervous  depression,  it  was  proved  that 
there  was  arsenicum  present  in  his  sleeping  apartment 
equal  in  amount  to  2  6  ounces  of  white  arsenic. 

These  poisonous  furnishing  materials  have  been  sold 
to  the  public  for  the  last  twenty  years. 

Children  have  been  poisoned  by  white  arsenic,  with 
which  "  violet  powder  "  has  been  found  to  be  adulterated 
to  the  extent  of  25  per  cent,  and  by  lead,  from  inhaling 
the  dust  that  proceeds  from  inferior  kinds  of  American 
cloth  with  which  perambulators  are  lined. 

The  public  is  exposed  to  danger  : — 

From  Arsenic 

in  the  employment  of  packs  of  cards,  enamelled  cooking 
utensils,  green  lamp  shades,  green  carpets,  green  Venetian 
blinds,  Berlin  wools  (green,  blue,  and  rose),  kindergarten 
toys,  candles,  water  colour  paints,  gloves  and  stockings 
(aniline  dyed),  papers  covering  confectionery,  glazed  paper 

1  Lancet,  August  11,  IS 77. 


262  SUSPENDED   ANIMAL,  VEGETABLE,  METALLIC 

collars,  and  starched  linen,  artificial  flowers  and  grass, 
anti-dry  rot  preparations,  etc. 

Arsenite  of  soda  and  arsenite  of  alumina  are  used  in 
calico-printing  and  fixing  the  colours. 

From  Lead 

in  the  use  of  soda-water,  lemonade,  beer,  tinfoil  around 
chocolate  and  other  sweets,  floor-cloths,  snuff,  tea, 
vermilion  red  flowers,  wall  paints,  American  imitation 
leather,  and  many  other  articles. 

Many  contrivances  have  been  devised  for  the  protec- 
tion of  the  lungs  of  workmen  who  have  to  support  "  dear 
life "  by  engaging  in  the  foregoing  and  other  unhealthy 
callings  ;  but  there  is  in  this  field  a  great  opportunity  for 
those  with  talents  for  invention  to  exercise  them  in  be- 
half of  these  suffering  thousands. 

In  addition,  the  ventilation  of  workshops  should  be 
more  attended  to,  for  at  present  the  admission  of  fresh, 
and  the  expulsion  of  foul,  air  is  about  the  last  thing 
thought  of.  Happily  something  has  been  done  in  this 
Knife-  direction  not  only  amongst  the  Sheffield  knife-grinders,"^ 
grinders.  |^^^^  ^^^  ^l^g  miucs  of  Durham  and  ISTorthumberland,  and 
the  gi^eatly  diminished  death-rate  of  these  poor  mechanics 

^  What  distressing  truths  have  been  for  years  presented  to  the  public 
by  the  late  Dr.  Hall,  of  Sheffield,  respecting  the  average  dirration  of  life 
amongst  the  steel-grinding  trades  of  that  city  !  "What  fearful  waste  of  life 
is  disclosed  in  Dr.  Wynter's  summary  of  Dr.  Hall's  observations  ! — "Dry 
grinders  of  forks,  29  years  :  razors,  31  years  ;  scissors,  32  years  ;  edge  tool 
and  wool  shears,  32  years  ;  spring  knives,  35  years  ;  files,  35  years  ;  saws, 
38  years  ;  sickles,  38  years."  Some  improvement  has  undoubtedly  been 
effected  of  late  years,  as  the  report  of  the  Medical  Officer  of  Health,  con- 
tained in  Dr.  Hall's  last  communication  to  the  profession  shows  ("Remarks 
on  the  Effects  of  the  Trades  of  Sheffield,"  Brit.  Med.  Journal,  October  14, 
1876),  through  the  introduction  of  fans,  but  much  still  remains  to  be 
done. 

In  1874,    92  grinders  died  ;  average  age  at  death,  46    years. 

In  1875,  111         ,,         „  „  ,,       42-5    ,, 


AND    MINERAL    IMPURITIES  263 

and  colliers  from  pulmonary  disease  proves  the  advantage 
of  free  ventilation. 

Sufficient  evidence  has  been  adduced  to  show  the 
magnitude  and  enormous  importance  of  the  subject. 
Medical  literature  and  the  columns  of  the  medical  press 
have  for  years  been  teeming  with  instances  of  the  whole- 
sale destruction  of  health  and  life  by  these  terribly 
dangerous  occupations.  In  brief,  the  mortality  induced 
by  impure  air  charged  with  poisonous  and  non-poisonous 
dusts  is  simply  an  ignorant  waste  of  human  life. 

The  air  that  we  breathe,  we  who  are  not  enoao^ed  in 
these  unwholesome  avocations,  is  full  of  dust — a  hetero- 
geneous mixture  of  particles  of  organic  and  inorganic 
origin. 

From  the  amount  of  spores  (250,000)  in  a  single  drop 
of  fluid,  Mr.  Dancer  calculated^  "that  37 J  millions  of 
these  bodies,  exclusive  of  other  substances,  were  collected 
from  2495  litres  =  88  cubic  feet  of  the  '  air  of  Manchester,' 
a  quantity  which  would  be  respired  in  about  ten  hours 
by  a  man  of  ordinary  size  when  actively  employed."  It 
may  well  be  said,  "  Surely  this  dust  that  we  all  of  us 
breathe  must  be  hurtful.  Is  there  no  pro\dsion  in  nature 
for  counteracting  its  baneful  influence  ?"  There  is  no 
doubt  but  that  the  less  of  it  we  have  the  better  for  us. 
We  are  taught  in  every  possible  way,  if  we  will  but  be 
guided  by  the  teachings  of  nature,  to  be  clean.  If  people 
will  but  admit  an  abundance  of  Nature's  great  disinfectant, 
pure  fresh  air,  into  their  houses,  and  at  the  same  time 
keep  themselves  and  their  houses  clean,  they  will  not  be 
injuriously  influenced  by  the  dust  of  the  air. 

^  "Microscopic  Examination  of  the  Solid  Particles  of  the  Air  of  Man- 
chester." Proc.  Lit.  and  PhUosopli.  Socy.  of  Manchester,  vol.  iv.  series  3, 
1867-68. 


CHAPTEE    XXIII 

EMANATIONS    FKOM    GEOUND    HAVING    DAMP   AND    FILTHY 
SUBSOIL SUBSOIL  AIE,  CHUKCHYARD  AIE,  MARSH  AIE 

The  air  of  towns,  and  also  that  of  Louses,  is  often  de- 
teriorated by  emanations  from  wet  and  filthy  subsoil.  It 
has  been  distinctly  proved  both  in  this  country  and  in 
America  that  the  death-rate  of  consumption  is  diminished 
very  considerably  by  drying  the  subsoil. 

Eheumatism,  and  heart-disease  which  is  so  frequent  a 
concomitant  of  rheumatic  affections,  are  lessened  by  the 
same  beneficial  measure.  Emanations  from  filthy  soil 
produce  diarrhoea  in  that  part  of  the  year,  namely  autumn, 
when  there  is  a  predisposition  to  intestinal  disorders.  It 
is  very  unwise  to  allow  the  soil  close  to  houses  to  be 
defiled  by  filth,  for  the  fires  of  a  house,  creating  a  force 
of  suction,  draw  into  the  house  the  air  contained  in  the 
surrounding  soil,  as  well  as  of  that  on  which  it  is  built. 
The  popular  impression  that  the  atmosphere  ends  where 
the  ground  begins  is  a  very  widely  spread  delusion. 
Most  soils  are  more  or  less  porous.  A  house  built  on  a 
gravelly  soil  stands  on  a  foundation  composed  of  a  mixture 
of  two  parts  of  small  stones,  and  one  part  of  air.  The 
air  may  give  place  to  any  gas  or  to  water.  The  porosity 
of  soils  may  be  well  illustrated  by  the  following  experi- 
ment devised  by  Pettenkofer.-^ 

^  Cliolera :  How  to  Prevent  and  Eesist  it,  by  Dr.  Max  von  Pettenkofer. 
Translated  by  Dr.  Hime. 


EMANATIONS    FEOM    DAMP    AND    FILTHY    SOIL 


26i 


"If  a  person  blows,  as  represented  in  the  figure,  on 
the  surface  of  the  gravel,  the  water  in  the  U-shaped  tube 
will  be  seen  to  alter  its  position,  the  level  of  the  side 
next  the  person  who  is  blowing  becoming  lowered,  and 
the  other  proportionately  elevated.  The  depression  of 
the  fluid  is  caused  by  the  force  of  the  air  blown  through 
the  gravel.     This  air  ascends   from   the   bottom  of  the 


Fig.  17. 

A,  a  tall  and  large  glass  tube  filled  with  fine  gravel,  in  the  axis  of  which  stands  a  very 
small  tube,  B,  open  at  both  extremities,  the  upper  being  curved,  and  connected  by 
a  piece  of  indiarubber  tubing,  C,  to  a  U-shaped  tube,  D,  containing  water.  B, 
fine  gravel. 

gravel  through  the  small  glass  tube,  passes  through  the 
indiarubber  tube,  and  thus  reaches  the  water." 

Eemembering  the  force  with  which  the  wind  often 
strikes  the  surface  of  the  ground,  with  a  pressure  during 
a  hurricane,  amounting,  according  to  some,  to  36,  and  to 
others,  of  50  pounds  on  every  square  foot,  it  cannot  be  a 
matter  of  surprise,  in  the  light  of  the  above  experiment, 
that  foul  and  pestiferous  air  from  the  filthy  earth  beneath, 
and  close  to  our  habitations,  should  be  introduced  into 
them,  aided,  as  this  driving  force  is,  by  the  suction  power 


266        EMANATIONS    FROM    DAMP    AND  FILTHY    SOIL 

created  by  the  fires  and  lamps,  etc.  I  have  encountered 
instances  in  which  foul  air  from  drains,  cesspools,  and 
from  leaky  gaspipes,  has  been  drawn  into  houses  great 
distances,  and  has  caused  ill-health  and  death  from  the 
continued  poisonous  condition  of  the  air.  Pettenkofer,  of 
Munich,  relates  a  case  -^  where  gas  was  found  to  have 
travelled  a  space  of  20  feet  from  the  street  main  into 
the  house. 

Dr.  F.  de  Chaumont  refers  ^  to  a  case  that  occurred  to 
Dr.  Fyffe,  in  which  the  foul  air  from  a  cesspool  was  sucked 
into  a  house  a  distance  of  27  feet. 

It  is  impossible  for  any  public  health  physician  to  speak 
in  temperate  language  of  the  crime  of  erecting  houses,  and 
of  allowing  houses  to  be  constructed,  on  filthy  and  sodden 
foundations.  No  one  can  possibly  enjoy  for  any  length  of 
time  good  health  in  such  buildings,  and  the  diseases  from 
which  the  inhabitants  suffer  are  generally  influenced  so  un- 
favourably by  the  insanitary  conditions  in  which  they  exist, 
as  to  have  a  tendency  to  death  rather  than  to  recovery. 
I  once  visited  a  little  town  on  the  coast,  swept  by  the 
purest  of  breezes — the  sea  breeze — where  scarlet  fever 
was  prevalent.  In  one  part  of  the  town,  where  the 
cottages  were  kept  in  a  cleanly  and  wholesome  state,  and 
were  built  on  virgin  soil,  the  disease  showed  itself  in  a 
mild  form,  and  not  a  death  occurred.  In  another  part  of 
the  town  nearly  every  family  lost  one  or  more  children, 
killed  almost  immediately  by  the  poison.  I  went  into 
one  of  the  cottages  where  all  the  children,  five  in  number, 
were  destroyed,  and  talked  to  the  poor  afflicted  parents. 
The  father,  pointing  to  a  loose  plank  of  the  floor,  moved 
a  portion  of  it  aside.  I  pushed  my  walking  stick  down, 
and  stirred  up  the  soil  over  which  this  family  had  been 
living.  It  was  fluid  filth.  The  cottages  in  which  these 
fatal  cases  occurred  had  been  erected  on  ground  made  up 
^  O}).  cit,  -  Lectures  an  State  Medicine. 


SUBSOIL   AIR 


267 


of  stinking  fish,  brickbats,  eartli,  and  every  kind  of  de- 
composing debris. 

Subsoil  Air. — The  chemical  composition  of  the  air  subsoii  air. 
contained  in  soils  ^  has  been  investigated  by  many  chemists, 
such  as  Boussingault  and  Lewy,  Pettenkofer,  Fleck  of 
Dresden,  Nichols  of  Massachusetts,  and  others.  A  large 
excess  of  carbonic  acid,  a  little  carburetted  hydrogen,  a 
trace  of  ammonia  and  hydrogen  sulphide  (when  the 
ground  water  possesses  sulphates),  have  been  discovered. 
They  all  seem  to  be  unanimous  as  to  the  much  greater 
quantity  of  carbonic  acid  in  ground  air  than  in  atmospheric 


Fig.  18. 


air,  and  as  to  its  great  variability  in  amount.  The  former 
fact  is  well  demonstrated  by  an  experiment  and  illustra- 
tion, contained  in  Mr.  W.  IST.  Hartley's  Air  and  its 
Relation  to  Life. 

A  flask  full  of  clear  baryta  water  is  connected  by 
tubes  to  a  vessel  filled  with  earth,  and  again  attached  to 
this  is  another  flask  of  baryta  solution.  By  drawing  air 
through  the  whole  system  of  bottles  the  amount  of  in- 
soluble carbonate  of  baryta,  formed  in  the  flrst  flask  by 
the  carbonic  acid  in  the  air,  may  be  compared  with  that 
in  the  second  flask,  produced  by  the  carbonic  acid  in  the  soil. 

^   Vide   Fodor's   Hygienische    Untersucliungcn  ubcr   Luft,   Bodcn  und 
Wasser,  2e  Abtlieilung  Boden  und  Wasser,  p.  99,  et  seq. 


268  CHUECHYARD    AND    MAESH    AIR 

Pettenkofer  discovered  that  the  amount  of  carbonic 
acid  in  ground  au'  varies  in  different  seasons  of  the  year, 
that  it  reaches  its  minimum  from  January  to  May,  and 
then  rises  steadily  to  its  maximum  from  July  to  Novem- 
ber. The  occurrence  of  the  maximum  in  autumn,  is 
.  probably  the  result  of  high  temperature  and  excess  of 
decomposing  organic  matter.  The  exact  period  of  the 
minimum  has  not  been  so  clearly  determined.  The 
analyses  of  the  air  of  soils  of  various  kinds  that  rest  on 
different  formations,  the  degree  of  porosity  of  soils,  and 
the  connection,  if  any,  of  the  same  with  such  diseases  as 
diarrhoea  and  certain  forms  of  continued  fever,  is  an 
extremely  interesting  field  for  research  which  has  been 
but  barely  opened  out.  That  there  is  a  very  decided 
relation  between  the  state  of  the  ground  air  and  the 
continued  prevalence  in  a  given  locality  of  diarrhoea  at 
certain  seasons  is  a  matter  of  strong  probability. 

It  has  been  suggested  that  the  amount  of  carbonic 
acid  in  ground  air  be  taken  as  indicative  of  the  degree  oi 
impurity.  As  the  animal  poisons  seem  to  attach  them- 
selves always  to  minute  particles  of  animal  and  vegetable 
organic  matter  in  a  state  of  decomposition,  a  study  of  the 
comparative  amount  of  organic  matter  in  the  ground  air 
of  soils  cannot  well  be  omitted. 

Churchyard  TJic  Air  of  ChurcJiyarcls  and  Vaults  is  richer  in  car- 
bonic acid  than  gTOund  air,  and  contains  often  a  putrid 
organic  vapour,  hydrogen  sulphide,  carbonate  of  ammonia 
and  sulphide  of  ammonium,  and  elementary  forms  of 
animal  and  vegetable  life. 

Marsh  air.  TJie  Air  of  Marshcs  contains  also  a  large  excess  of 

carbonic  acid  and  organic  matter.  The  experimental 
evidence  which  at  present  exists  as  to  the  presence  of  a 
bacillus  malariffi  (Klebs)  in  the  air  of  marshes  where 
ague  abounds,  and  as  to  its  existence  in  the  blood  of  those 
suffering   from   this    disease,   is   insufficient   and   uncon- 


CHURCHYARD    AND    MARSH    AIR  2G9 

vincing.-^  Great  quantities  of  living  organisms  and 
organic  debris,  carried  upward  for  a  certain  distance  by 
the  ascensional  force  afforded  by  the  evaporation  of  water, 
are  discernible  on  microscopic  examination.  Carburetted 
and  phosphuretted  hydrogen  gases  are  evolved  by  marsh 
land,  and  sometimes  hydrogen  and  ammonia.  The  time 
to  be  selected  for  making  observations  on  the  composition 
of  marsh  air  is  in  the  early  morning  or  evening,  when  the 
density  of  the  air  and  the  deposition  of  dew  prevents  a 
free  admixture  of  the  impure  with  the  higher  strata  of 
pure  air,  or  during  a  hot,  sultry  noon  when  no  breeze 
keeps  the  air  in  motion.  I  have  made  analyses  of  the 
air  of  marshes  that  are  hotbeds  of  ague,  taken  on  a  fine 
day,  whilst  a  gentle  wind  blew  over  them,  and  have 
found  no  more  organic  matter  in  such  air  than  in  pure 
air  collected  simultaneously  on  high  hills.  This  fact  is 
only  another  proof  of  the  marvellous  purifying  properties 
of  air,  and  the  tendency  throughout  nature,  not  only  in 
the  air,  but  in  the  earth  and  in  water,  to  self-purification, 
and  to  the  restoration  of  an  equilibrium. 

^  Vide  information  on  this  subject  in  Dr.  H.  Gradle's  Tvork  on  Bacteria 
and  Tourmasi-Crudeli's  illustrations,  in  Joicrnal  d' Hygiene  of  March  31, 
1881. 


CHAPTEE  XXIV 

THE  DELETERIOUS  EFFECTS  ON  HEALTH  OF  THE 
AIE  OF  OUE  HOUSES 

The  air  of  ^o  dilate  Oil  sucli  a  subject  would  be  indeed  needless  to 
students  of  preventive  medicine,  if  a  general  recognition 
existed  of  tbe  fundamental  principles  on  whicb  the  re- 
lations between  a  state  of  health  and  disease,  and  between 
a  condition  of  health  and  the  circumstances  which  tend 
to  promote  and  deteriorate  it,  rest.  The  old  notion  that 
disease  is  a  sort  of  maKgnant  demon  that  takes  possession 
of  the  body,  and  requires  to  be  combated  and  exj)elled  by 
some  violent  means,  is  still  a  very  widespread  one,  even 
amongst  some  of  the  rural  rank  and  file  of  the  medical 
profession,  and  any  modern  ideas  as  to  the  relations  of 
health  to  the  conditions  of  those  surroundings  of  life, 
namely,  the  air  we  breathe,  the  water  we  drink,  and  the 
food  we  eat,  which  so  seriously  influence  it  for  good  or 
evil,  are  often  received  with  a  smile  of  incredulity.  The 
public  surely  ought  not  to  require  a  skilful  physician  to 
teach  them  what  common-sense  inculcates,  that  perfect 
bodily  and  mental  health  cannot  be  enjoyed  by  those  who 
are  inattentive  to  the  cleanliness  of  the  body,  and  of  that 
which  enters  it.  There  is,  unhappily,  an  increasingly 
exaggerated  importance  attached  at  the  present  time,  by 
great  numbers  of  people,  to  the  injurious  effects  of  impure 
water.      It  is  the  fashion  to  ascribe  almost  every  indis- 


THE  AIR    OF    OUK    HOUSES  27l 

position  to  the  condition  of  the  water  supply.  The  ten- 
dency to  run  into  extremes  about  most  matters,  and  to 
ride  hobbies,  is  but  too  frequently  observed.  On  the  other 
hand,  there  does  not  yet  exist  in  the  public  mind  an 
adequate  conception  of  the  extent  of  the  danger  to  the 
health  which  is  induced  by  a  continual  immersion  of 
the  body  in  impure  air,  notwithstanding  the  efforts  that 
have  been  made  in  this  direction  for  the  enlightenment 
of  the  public  mind.  For  a  quarter  of  a  century  I  have 
been  preachiug  on  this  subject,  pretty  much  in  the 
language  of  my  First  Annual  Eeport  as  Medical  Officer  of 
Health  for  1874,  which  contains  the  following  passages: — Theteaching 
"  It  should  not  be  necessary  to  point  out  the  blessings  o^g^g*'^ 
of  pure  air,  and  the  e^dls  resulting  from  the  inhalation 
of  a  vitiated  atmosphere.  Excluding  from  consideration 
the  effects  of  an  exposure  to  the  foetid  gases  of  organic 
decomposition,  which  act  like  other  poisonous  chemical 
agents,  it  may  be  said  that  offensive  smells,  the  products 
of  putrefaction,  are  not  only  injurious  in  themselves,  but 
serve  as  danger  signals  bidding  men  to  beware.  By 
acting  as  depressants,  and  as  reducers  of  bodily  Adgour, 
they  tend  to  make  the  system  more  prone  to  be  attacked 
by  disease.  As  the  smell  of  gas  in  a  house  warns  men 
of  the  presence  of  a  body  dangerous  when  diffused 
through  it,  so  an  offensive  smell  is  a  signal  of  the  possi- 
bility of  the  presence  of  the  poison  of  a  disease.  A 
stench  may  or  may  not  be  associated  with  a  disease 
poison,  and  no  one  knows  when  it  is  and  when  it  is  not 
thus  accompanied.  As  a  means  of  warning  to  those 
exposed,  an  offensive  smell  is  useful,  but  we  must  re- 
member that  agents  which  destroy  the  stink  of  filth  may 
yet  leave  all  its  powers  of  disease-production  undiminished. 
Disease  poisons  or  ferments,  although  not  alw^ays  in  the 
companionship  of  stinks,  are  often  so,  and  it  behoves 
every  one  to  remove   the  cause  of  stinks,  and  prevent 


272         THE    DELETERIOUS    EFFECTS    ON    HEALTH    OF 

their  recurrence.  Disease  fernients  may  fatally  assail  the 
human  body  in  closes  quite  unappreciable  to  the  most 
acute  sense  of  smell.  All  unpleasant  smells  are  to  a 
certain  extent  deleterious,  although  infinitesimally  so 
perhaps.  Pleasant  odours,  if  in  excess,  become  injurious 
to  some  persons.  Those  who  visit  the  farms  devoted  to 
the  cultivation  on  a  large  scale  of  the  rose  and  jessamine 
in  France,  for  the  manufacture  of  scents,  experience,  after 
being  exposed  to  these  perfumes  for  a  little  time,  severe 
frontal  headache  and  lassitude,  symptoms  which  speedily 
pass  away  when  they  emerge  from  these  odoriferous  tracts 
of  country.  It  should  always  be  remembered,  then,  that 
smells  which  offend  the  senses,  even  when  not  accom- 
panied by  disease  poisons,  act  deleteriously  on  the  health 
of  those  frequently  exposed  to  them,  by  depressing  the 
system,  thereby  lessening  the  resistance  of  the  frame  to 
the  approach  of  disease,  and  by  diminishing  the  bodily 
vigour,  rendering  the  vis  medicatrix  naturae  a  less  chance 
of  success  in  preventing  disease  from  destroying  those 
attacked." 

The  effect  of  all  the  exertions  of  that  class  who  have 
been  called  sanitary  reformers  is,  that  large  numbers  of 
people  tacitly  acknowledge  that  the  constant  inhalation 
of  air  rendered  impure  to  the  senses  of  sight  and  smell  is 
Result  of.    likely  to  injure.      It  seems  very  difficult  for  the  public  to 
amoiF^ttiiego  a  stcp  further  and  cease  to   offer  opposition  to  the 
public.        behef  which  is  rooted  in  the  mind  of  every  public  health 
physician,  that  frequent  exposure  of  the  body  to  air  that 
is  deteriorated  in  quality  either  by  having  been  rebreathed 
without  purification,  or  devitalised,  tends  to  a  reduction 
of  the  vital  powers,  a  state  which  is  favourable  to  the 
development  of  a  perversion  of  healthy  action,  the  pre- 
cursor of  disease. 

Dr.    Eichardson    has,   in    his    attractive    style,    most 
candidly  spoken  out   on  this   subject   in  his  Diseases  of 


THE    AIR    OF    OUR    HOUSES  273 

Modem  Life.  "  It  is  this  devitalised  air  in  our  over-  r»r.  Richard- 
crowded  towns  and  cities,  where  there  is  no  vegetation  of"he^uni-'^ ' 
to  revivify  it,  which  we  distinguish  as  something  so  dif-  ^'"^ai  sys- 

■^        '  ^.  ^  temofair 

lerent  from  the  fresh  country  air  that  streams  over  forest  deteriora- 
and  meadow.  It  is  the  breathing  of  this  air  that  makes  *'™" 
the  child  of  the  close  town  so  pale  and  lax  and  feeble,  as 
compared  with  the  child  of  the  country.  It  is  this  air 
that  renders  the  atmosphere  of  the  crowded  hospital  so 
deficient  in  sustaining  power.  It  is  this  air  that  gives  to 
many  of  our  public  institutions,  in  which  large  numbers 
of  our  poorer,  ill-clad,  uncleansed  masses  are  herded 
together,  that  'poor  smell,'  as  it  is  called,  which  is  so 
depressing  both  to  the  senses  and  to  the  animal  power. 

"  In  many  private  houses,  houses  even  of  the  well-to- 
do  and  wealthy,  streams  of  devitalised  air  are  nursed  with 
the  utmost  care.  There  is  the  lumber-room  of  the  house, 
in  which  all  kinds  of  incongruous  things  are  huddled 
away,  and  excluded  from  light  and  fresh  air.  There  are 
dark  understairs  closets,  in  which  cast-off  clothes,  charged 
with  organic  debris  of  the  body,  are  let  rest  for  days,  or 
even  weeks,  together.  There  are  bedrooms  overstocked 
with  furniture,  the  floors  covered  with  heavy  carpets,  in 
which  are  collected  pounds  upon  pounds  of  organic  dust. 
There  are  dressing-rooms,  in  which  are  stowed  away  old 
shoes  and  well-packed  drawers  of  well-worn  clothing. 
There  are  dining-rooms,  in  which  the  odour  of  the  latest 
meal  is  never  absent,  and  from  the  cupboards  of  which 
the  smell  of  decomposing  fruit  or  cheese  is  always  eman- 
ating. There  are  drawing-rooms,  in  which  the  scent  of 
decayed  roses,  or  of  the  varnish  from  the  furniture,  or  of 
the  dye  from  the  table-covers,  is  always  present.  There 
are  kitchens  in  which  there  is  the  odorous  indication  of 
perpetual  cooking.  There  are  sculleries  where  the 
process  of  '  washing  up '  seems  to  be  in  permanent  action, 
and  where   the   products  of  change   from  stored   bones, 

T 


274         THE    DELETERIOUS    EFFECTS    ON    HEALTH    OF 

potato  parings,  recent  vegetable  green  food,  and  other 
similar  refuse,  are  abiding.  There  are  water-closets  in 
which  there  is  at  every  time  of  daj  or  night  a  persistent, 
faint  ammoniacal  organic  odour. 

"  The  process  of  devitalisation  of  the  air  is  again 
effected,  locally,  in  human  habitations,  by  the  presence  in 
it  of  the  lower  forms  of  life.  When  in  the  dwelling- 
house  dogs,  cats,  tame  mice,  birds,  squirrels,  are  kept  in 
such  numbers  that  the  odours  of  the  animals  are  percep- 
tible ;  when  flies  cover  the  ceilings,  and  a  mould  collects 
on  the  walls,  then  the  air  teems  with  myriads  of  minute 
living  forms,  and  with  organic  dust.  Every  particle  of 
this  matter  induces  deterioration  of  the  air  that  feeds  the 
lungs." 

Although  many  may  smile  on  reading  the  foregoing 
extract,  every  one  with  any  experience  of  life  must  admit 
the  truthfulness  and  fidelity  of  the  sketch.  The  prin- 
ciples that  should  be  firmly  implanted  in  our  minds  are 
involved  in  the  consideration  of  such  golden  rules  as  the 
following : — 
w?th°wMch  -'-•  -^^®  exposure  of  the  body  continually  to  a  smell,  be 
the  public  it  a  pleasant  or  an  unpleasant  one,  is  deleterious  to 

mind  should  ■■        -•,  ■■ 

be  imbued.  -Heaitn. 

2.  An    odour   that    is    at   first   pleasant,   generally   soon 

becomes  objectionable.  The  little  is  grateful,  but  a 
constant  excess  of  the  perfume  is  hurtful. 

3.  An  unpleasant  odour  may  or  may  not  be  in  the  com- 

panionship of  a  disease  ferment,  and  no  one  knows 
when  it  is  or  when  it  is  not  so  accompanied.  The 
putrid  gases  of  decomposition  will  not  in  themselves 
give  rise  to  the  development  of  either  of  the  zymotic 
diseases. 

4.  When  an  unpleasant  odour  is  not  associated  with  a 

poison  of  a  disease,  it  is  nevertheless  deleterious  to 
the  health  of  those  constantly  subjected  to  its  in- 


THE    AIE    OF    OUK    HOUSES  2  /  5 

fluence.  I  know  that  this  statement  will  be  doubted 
by  some.  Several  instances  of  its  truth  have  oc- 
curred to  me.  For  example,  a  man  in  good  health 
took  a  house  close  to  one  of  those  public  trade 
nuisances  where  the  smell  of  melted  tallow  taints 
the  air,  and  suffered  in  consequence  severely  from 
nausea  and  diarrhoea.  Here  no  septic  ferment  could 
have  existed,  such,  for  example,  as  is  supposed,  with 
good  reason,  to  be  mingled  with  the  odours  of  the 
dissecting-room. 

5.  The  healthy  human  body  often  becomes  inured,  after 

long  exposure,  to  un|)leasant  odours,  and  at  length 
hardly  notices  them,  if  always  immersed  in  them. 
Those  actively  injurious  effects  of  impure  air,  such 
as  nausea,  diarrhoea,  etc.,  often  gradually  pass  away. 
If  a  man  is  possessed  of  exceptional  powers  of 
vigour,  which  enable  him  to  maintain  a  successful 
warfare  with  those  depressing  influences  that 
surround  him,  he  may  live  for  a  great  many  years 
in  tolerable  health,  although  defying  the  laws  of 
nature.  The  large  majority  become  affected  in 
course  of  time,  if  not  suddenly  attacked  by  a  passing 
epidemic  (to  which  a  person  living  under  unhealthy 
conditions  is  especially  prone),  by  the  insidious 
progress  of  a  chronic  disease. 

6.  Air,  which  is  not  defiled  by  the  offensive  productions 

of  decomposition,  may  contain  organic  matter  in  the 
form  of  dust  or  vaporous  emanations,  as  carriers  of 
the  specific  poisons. 

A  cursory  examination  of  these  dicta  may  lead  some 
one  who  is  indisposed  to  remove  a  nuisance  from  his  pre- 
mises to  urge  that  the  wdiole  question  as  to  whether  an 
odour  is  or  is  not  injurious  to  health,  rests  on  the  point 
as  to  whether  it  does  or  does  not  annoy  the  person  con- 


276  THE    DELETERIOUS    EFFECTS    OX    HEALTH    OF 

tinually  exposed  to  it.  Anytliing  wliicli  persistently 
worries,  disturbs,  and  irritates,  is  undoubtedly  dele- 
terious to  health,  although  the  injury  may  be  so  in- 
finitesimal that  it  cannot  perhaps  be  measured  or 
demonstrated.  It  will  probably  scarcely  incommode 
the  resilient  disposition  of  the  young  and  healthy 
animal  that  is  naturally  cheerful,  and  disposed  to  look 
on  everything  with  a  couleur  de  rose  hue.  The  human 
body  by  acclimatization  can  adapt  itself  to  wondrously 
different  circumstances,  although  a  certain  injury  is 
received  by  so  doing,  but  it  never  reaches  the  period  of 
old  age  if  continually  bathed  in  impure  air,  although  that 
air  may  have  long  ago  ceased  to  offend  the  olfactory 
nerves.  The  comparative  freedom  of  the  sewer  men  of 
Paris  from  cholera  and  other  z}Tnotic  diseases,  the 
absence  of  any  marked  injury  to  health  during  the  year 
that  the  Thames  was  so  odoriferous,  and  of  any  excess 
of  zymotic  disease  in  the  neighbourhood  of  Moatfaucon, 
in  Paris,  where  much  of  the  filth  of  that  city  is  stored 
jDreparatory  to  its  conversion  into  manure  for  agricultural 
purposes — assertions  which  have  encouraged  the  opinion 
that  a  constant  exposure  to  morbific  ferments  or  contagia 
diminishes  the  risk  of  being  injured  by  them — will 
perhaps  be  urged  as  contradicting  these  views.  It  is  a 
well  -  established  rule,  however,  notwithstanding  the 
existence  of  certain  much-talked-of  supposed  exceptions, 
which  is  recognised  by  the  whole  of  the  medical  pro- 
fession, that  there  is  a  gi-eater  mortality  amoiigst  those 
who  are  exposed  continually  to  impure  air  than  with 
others  who  are  not  so  circumstanced,  and  that  the 
diseases  from  which  the  former  suffer  are  of  an  asthenic 
type  tending  to  death  rather  than  to  recovery. 
Air  of  the  Tlic  amount  of  oxygen  in  the  air  is  diminished,  and 

town!^and    ^^^^^  °^  ^^®  carbouic  acid  is  increased  by  respiration,  and 
cities  is  not  combustiou  and  decay  of  organic  matter,  the  former,  to 


THE    AIR    OF    OUR    HOUSES  277 

speak    in    popular    language,    being    tlie    lifegiving    and  so  impure  as 
purifying  principle,  and  the  latter  its  noxious  substitute,  generaii^ 
Thanks  to  the  diffusive  powers  of  gases,  and  the  effects  of  thought, 
wind,  and  to  the  currents  produced  by  the  fires  of  large 
towns,  and  last,  but  not  least,  to  the  wonderful  cleansing 
properties  of  fresh  air,  the  air  of  the  streets  of  our  towns 
is  not  so  impure  as  might  be  expected.      The  air  of  our  An-  of  our  i 
houses,   on   the    other   hand,   is   generally  very   impure,  exwbitifthe 
because  the  continuous  admission  into  them  of  pure  air,  presence  of 
and  expulsion  of  that  which  has  been  used  up,  is  rarely  amounts  of 
thought  of,  or  if  so,  is  seldom  efficiently  managed.      In  deflimg 
respiration  we  deteriorate  an  enormous  quantity  of  air 
(about    a    gallon    a    minute),    and    we    are    continually 
throwing  off  carbonic  acid  and  organic  matter.      Every 
time  we  breathe,  and  we  breathe  about  eighteen  times  per 
minute,  we  expel  30  cubic  inches  of  air,  which  amount 
contains  1"29  cubic  inch  of  carbonic  acid,  or  16"1  cubic 
feet  in  the  24  hours.      In  the  16  cubic  feet  of  carbonic 
acid,  there  are  about  7-2-  ounces  by  weight  of  charcoal. 
Others  say  that  the  amount  of  charcoal  is   160  gxains 
per  hour  =  8  ounces  in  24  hours.     Air  which  has  been 
once  breathed  should  never  be  breathed  again  until  it  has 
been  mingled  with  fresh  air,  in  order  that  the  impurity 
which  it  has  acquired  may  be  removed  from  it,  and  that 
it  may  regain  a  wholesome  amount   of  moisture.      The 
overcrowding  of  schoolrooms  is  a  subject  respecting  which 
much  has  been  said  in  the  way  of  protest  for  years.      It 
has  been  shown  by  Eoscoe  in  his  experiments  on  the  air 
of    schoolrooms   that   10  cubic   feet   of   air   per    minute 
per  head  is  insufficient  to  remove  completely  the  organic 
putrescent  matter,  and  yet  schoolrooms  are  to  lie  found 
where  there  is  even  less  than  4  cubic  feet  for  each  child. 
Architects  design  houses,  local  boards  pass  the  plans, 
builders    erect    places    which   are   totally   devoid    of    all 
provision   for   the    admission   of  fresh  air,  and   may  be 


except  in 
the  crudest 
manner. 


278         THE    DELETEPJOUS    EFFECTS    O'N    HEALTH    OF 

likened  to  Holes  of  Calcutta  on  the  small  scale.  As  for 
arranging  for  a  change  of  air  by  the  passage  through  a 
room  of  warmed  fresh  air  in  winter,  and  cooled  fresh 
air  in  summer  of  a  healthful  degree  of  humidity,  such  a 
proceeding  is  never  dreamt  of.  The  drowsiness  which 
often  oppresses  our  congregations  may  frequently  be  more 
Absence  of  correctly  ascribed  to  the  absence  of  any  attempt  at 
*"^  ^**.^"li' Ventilation  than  to  the   cause  to  which  it  is   generally 

to  ventilate  ^  "^ 

buildings  attributed.  Who  is  there  not  acquainted  with  the  un- 
wholesome atmosphere  to  be  met  with  in  nearly  every 
public  building  ?  whilst  our  drawing-rooms,  dining-rooms, 
and  bedrooms,  even  in  the  best  houses,  are  too  often  in  a 
most  disagreeable  state  of  what  is  termed  "  closeness." 
On  once  remonstrating  with  the  verger  of  a  church  in  a 
suburb  of  London  with  respect  to  the  oppressive  state  of 
the  air  during  the  Sunday  afternoon,  and  on  suggesting 
to  him  the  propriety  of  opening  freely  the  windows 
duriuCT  the  interval  between  the  first  and  second  services, 
he  expressed  his  disapproval  of  my  proposition  by  in- 
forming me  that  if  he  followed  my  advice  "  the  church 
would  catch  a  chill." 

I  have  always  maintained,  and  increased  experience 
has  only  confirmed  my  previous  conviction,  that  the 
impure  condition  of  the  air  of  our  houses,  be  they 
factories,  public  buildings,  or  dwelling-houses,  has  much 
to  do  with  the  great  prevalence  of  such  diseases  as 
phtliisis  pulmonalis,  bronchitis,  and  pneumonia,  which 
together  make  up  nearly  one  quarter  of  the  total  mor- 
tahty ;  and  if  we  could  strike  a  telling  blow  at  that 
great  universal  evil — namely,  poisoning  by  impure  air 
— we  should  do  much  to  save  life.  Unventilated  and 
overcrowded  workshops  and  schools  are,  moreover,  the 
nurseries  of  strumous  diseases  in  general,  which  sap  the 
strength  of  the  community. 

During  the  decennial  period  1865  to  1874,  not  less 


THE    AIR    OF    OUR    HOUSES  279 

than  half  a  million  individuals  died  of  phthisis,  and 
three-quarters  of  a  million  of  people  were  destroyed  by 
other  diseases  of  the  lungs  in  England.  The  dependence 
of  these  diseases  on  vitiated  air  was  maintained  by  Dr. 
AHson^  as  long  ago  as  1824,  by  Baudelocque  in  1834,^ 
and  very  likely  long  before  those  years. 

The  facts  that  an  increase  of  phthisis  pulmonalis  occurs  Phthisis 

■  J_^  •  •        J.^         1  -J.         r  i       pulmonalis. 

^an  passu  with  an  mcrease  m  the  density  oi  a  popula- 
tion ;  that  in  manufacturing  centres,  where  the  males 
are  the  chief  workers  at  indoor  employment,  the  male 
death-rate  is  the  highest ;  and  in  others,  where  females 
are  principally  required  at  indoor  work,  they  suffer 
most ;  that  in  agricultural  districts,  where  the  men 
spend  nearly  all  their  lives  in  the  open  air,  and  the 
women  scarcely  ever  leave  their  cottages,  the  female 
death-rate  from  this  disease  is  higher  than  the  male : — 
all  point  to  this  inevitable  conclusion. 

Dr.  Parkes  mentions  a  remarkable  cuxumstance 
illustrative  of  this  connection  as  having  occurred  in 
Vienna.  In  the  badly-ventilated  prison  of  Leopold- 
stadt,  51  "4  per  1000,  whilst  in  the  well -ventilated 
House  of  Correction  of  this  city,  7 "9  per  1000  died  of 
consumption. 

Dr.  Guy's  evidence  before  the  Health  of  Towns 
Commission  contained  most  striking  statements  as  to  the 
journeymen  printers  of  London.  He  divided  them  mto 
three  classes : — 

The  1st  Class  consisted  of  men  who  worked  in  rooms 
where  they  had  less  than  500  cubic  feet  of  air  per  head. 
Of  these  12-|-  per  cent  had  spat  blood,  and  a  like  pro- 
portion had  been  subject  to  catarrh. 

The  '2cl  Class  comprised  men  who  had  between 
5  0  0    and    6  0  0    cubic    feet    of    breathing    space    per 

^  Edinhiorgh  Meclico-CMrurgical  Transactions,  vol.  i. 
-  Etudes  sur  la  maladie  scrophulciisc. 


280         THE    DELETEEIOUS    EFFECTS    ON    HEALTH    OF 

individual,  and  amongst  them  intermediate  effects  were 
noticed. 

The  3d  Class  was  composed  of  men  who  worked  in 
sliops  where  they  had  more  than  600  cubic  feet  per 
individual,  and  amongst  these  only  4  per  cent  had 
suffered  from  spitting  blood,  and  only  2  per  cent  from 
catarrh. 

The  published  opinions  of  Dr.  Farr,  Dr.  Marcet,  Mr. 
Welch,-^  Dr.  Eansome,^  Dr.  Parkes,  Dr.  Austin  Flint, 
and  Sir  James  Clark,  are  all  to  the  same  effect. 

The  continued  employment  of  rebreathed  air  for 
respiratory  purposes,  and  its  bearing  on  the  develop- 
ment of  that  terribly  fatal  strumous  disease,  pulmonary 
consumption,  has  been  vigorously  brought  before  the 
world  by  the  late  Dr.  MacCormack,  of  Belfast,^  who,  to 
show  his  enmity  to  used-up  air,  was  said  to  sleep  always, 
during  winter  and  summer,  as  did  also  his  family,  with 
the  windows  of  their  bedrooms  widely  opened. 

The  testimony  of  the  most  able  physicians  of  this 
and  other  countries ;  the  results  of  inquiries  as  to  the 
prevalence  of  this  disease  amongst  the  picked  men  of  the 
armies  and  navies  of  the  world ;  the  reports  of  hospitals 
for  consumption,  and  of  commissions  and  committees  ap- 
pointed to  make  special  investigations  as  to  jails,  work- 
houses, and  schools :  all,  in  various  degrees,  corroborate 
this  opinion.  There  are  one  or  two  apparent  exceptions 
to  this  rule  in  Iceland  and  the  Hebrides,  which  are 
worthy  of  attentive  consideration.*     The  beneficial  effects 

^  "On  the  Nature  and  Variations  of  Destructive  Lung  Disease,  as  seen 
amongst  Soldiers,  and  the  hj'gienic  conditions  under  which  they  occur." 

^  ''  Foul  Air  and  Lung  Disease." 

^  "  Consumption,  as  engendered  by  rebreathed  air." 

*  Vide  Dr.  Morgan,  on  the  "  ISTon-prevalence  of  Phthisis  in  the  Heb- 
rides and  along  the  N.W.  Coast  of  Scotland." — Brit,  and  Foreign  Medico- 
Cliirurgical  Review,  1860,  vol.  xxvi.  p.  483. 

Vide  controversy  in  Medical  Periodicals,  during  1S68  and  1869,  between 


THE    AIR    OF    OUR    HOUSES  281 

on  tliis  disease  of  sea  air,  the  air  of  high  latitudes 
and  elevated  regions,  furnish  an  indication  as  to  its 
cause. 

That  impure  air  vitiated  by  respiration  is  the  one  great 
cause  of  pulmonary  consumption,  which  may  be  trans- 
mitted from  parents  to  children  for  generations,  needs  no 
proof,  as  it  rests  on  such  a  mass  of  evidence.  It  is 
probable  that  foul  air,  by  impairing  the  appetite  and 
thus  hindering  nutrition,  may  render  the  body  suscep- 
tible to  the  development  of  the  virus  peculiar  to  the 
disease. 

If  it  should  ultimately  be  shown  that  the  bacillus 
tuberculosis  (vide  page  3  0  6)  is  the  agent  contained  therein, 
through  which  the  poison  of  phthisis  pulmonalis  is  com- 
municated from  one  individual  to  another,  still  further 
confirmation  would  be  afforded  as  to  its  causation. 
Pathogenic  micro-organisms,  whilst  influenced  by  tem- 
perature and  other  circumstances,  flourish  in  media 
containing  organic  matter,  accordingly  a  pure  air  is  not 
so  likely  as  an  impure  one,  either  to  contain  nourishment 
for  any  elementary  forms  of  life  productive  of  disease,  or 
to  be  the  carriers  of  the  same.  Dr.  Fuller  writes  ^  "  the 
more  closely  human  beings  are  congregated  together  the 
more  abundant  will  be  that  wonderful  micro-organic  life 
which  goes  on  unseen,  and  often  unheeded,  around  us 
and  about  us,  exerting  its  baneful  influence  on  the 
crowded  millions  packed  away  in  our  great  cities  in- 
sidiously eating  away  their  lives  with  consumption." 

Some  animals  that  are  kept  for  a  long  time  in  con- 
finement are  affected  in  a  manner  similar  to  man.  The 
monkeys  of  our  Zoological  Gardens  are  well  known  to 
die  in  great  numbers  from  this  disease.     Dairy  cows  that 

tlie  late  Dr.  MacCormack,  Dr.  Leared,  Dr.  Hjalteliu,  aud  others,  as  to 
Avhether  Phthisis  is  or  is  not  indigenous  in  Iceland. 

^  Soxiih  Africa  as  a  Health  Ecsort. 


282         THE   DELETERIOUS    EFFECTS    ON    HEALTH    OF 

are  kept  immured  in  close,  ill-ventilated  slieds  in  cities 
and  towns  also  suffer  from  a  form  of  tuberculosis.^ 
strumous  As  regards  the  connection  between  the  other  strumous 

diseases  and    t  -,  t  iij_  ly    •      j.      i        i}  i 

overcrowd-  discascs  and  overcrowding,  abundant  proof  is  to  be  found 
^'is-  if  looked  for.      Scrofula  once  prevailed  to  such  an  extent 

in  the  Asylum  of  the  house  of  Industry,  Dublin  (so 
Carmichael  aflirms),  that  it  was  regarded  as  a  contagious 
complaint.  The  air  was  so  impure  in  consequence  of  the 
excessive  overcrowding  as  to  be  unendurable  when  the 
wards  were  first  opened  in  the  morning,  and  to  be  "  but 
little  better  "  during  the  day  time. 

The  communicable  eye  disease,  so  common  in  asylums 
and  schools  for  children,  is  another  of  the  legacies  of  our 
overcrowding.  The  injurious  effects  of  rebreathed  air,  and 
the  want  of  any  provision  for  ventilation,  is  not  only 
seen  in  the  public  schools  for  the  poor,  but  in  private 
schools  for  middle  classes.  I  once  visited  a  "  College  for 
Young  Ladies,"  which  contained  rooms  12  ft.  X  9  ft.  x  8 
ft.  high,  in  each  of  which  slept  six  girls,  between  the  ages 
of  10  and  17,  in  two  beds.  ISTot  a  fireplace  or  other 
means  of  ventilation  existed.  This  school,  which  was  a 
popular  one,  had,  like  a  concertina,  a  wonderful  power  of 
expansion — those  who  could  not  be  accommodated  with 
beds  being  stowed  away  on  floors  and  in  day  rooms. 
That  young  women,  at  the  most  delicate  period  of  their 
lives,  should  be  thus  injured  by  thoughtless  parents,  who 
care  more  for  the  cheap  purchase  of  a  smattering  of  ac- 
complishments than  a  healthy  frame,  is  a  great  evil. 
Every  school  should  be  under  the  supervision  of  the 
Health  Authority  of  the  district  in  which  it  is  situated, 
so  that  a  guarantee  may  be  afforded  to  the  State  that  the 
young  be  not  subjected  to  the  cruelty  of  slow  poisoning 
by  foul  air. 

The  relation  between  such  lung  diseases  as  bronchitis 
•^  Tide  Annalcs  d' Hygiene,  voL  ii.  p.  447. 


THE    AIR    OF    OUR    HOUSES  283 

and   pneumonia,  and   the  unwholesome  condition  of  the  Diseases  of 
air  of  our  dwellings,  has  not  been  sufficiently  recognized  hyJ,rlanTlnd 
the  medical  profession  and  the  public.      One  of  the  most  i^p^^e  air. 
common   causes  of  an   attack  of  bronchitis  is  a  sudden 
exposure  of  the  bronchial  mucous  membrane  to  extreme 
meteorological  conditions  of  air.     A  man  who  breathes 
for  some  hours  the  hot  and  dry  vitiated  air  of  an  un- 
ventilated  room  is  prone  to  be  thus  affected  on  passing  out 
into  cold  damp  night  air.      If  debilitated  from  any  cause, 
the  inflammation  may  affect  the  substance  of  the  lung,  and 
the  man  will  have  pneumonia. 

Eapid  alternations  of  temperature  and  moisture  are  apt 
to  be  attended  with  risk  to  health  to  those  who  have 
passed  the  period  of  youth  during  which  the  body  quickly 
adapts  itself  to  altered  atmospheric  conditions.  The  body, 
in  the  middle-aged  and  old,  always  experiences  a  difficulty 
in  suddenly  accommodating  itself  to  extreme  ranges  of 
temperature.  By  substituting  for  the  overheated  and 
impure  air  of  our  houses  and  public  buildings  a  pure 
wholesome  air,  of  a  temperature  adapted  to  our  sensations 
of  comfort,  by  the  establishment  of  an  efficient  system  of 
ventilation,  we  shall  avoid  the  danger  of  sudden  and 
extreme  changes  which  continually  menaces  those  organs 
in  which  the  blood  and  air  meet. 

A  Fellow  of  the  Eoyal  Society  has  recently  publicly 
declared  that  there  is  not  a  perfectly  healthy  dwelling- 
house  in  the  country.  Although  that  at  first  sight  seems 
an  exaggerated  view,  yet  it  is  not  far  short  of  the  truth. 
I  only  know  of  one  room  in  this  country  in  which  there  *^"<^  ^^ii- 

.,      .  .  ,         ^^   "^  o    ^  ventilated 

IS  any  good  ventilation,  namely,  the  House  oi  Commons,  room  iutue 
All    the   patents  that   have  ever   yet   been   devised   are  ^°'^"^''^'" 
inefficient     and    faulty,    although     some    very    elaborate 
ventilating  and  warming  arrangements  for  the  comfort  of 
guests    have   of   late  been    established    in    some   of  the 
continental  health  resorts,  notably  at  the  large  Kursaal  on 


284         THE    DELETERIOUS    EFFECTS    OX    HEALTH    OF 

useiessness  the  Maloja  plateau  of  the  Upper  Engadine.  Amongst  the 
dozens  of  contrivances  that  are  described  and  figured  in  F. 
Edwards'  book,  entitled  Ventilation  and  Heat,  not  one  ful- 
fils the  requirements  of  a  good  ventilator,  namely,  the  con- 
stant passage  into  each  room  of  pure  air  of  a  healthful  degree 
of  humidity — warmed  in  winter  and  cooled  in  summer — 
with  an  accompanying  provision  for  the  immediate 
removal  of  that  which  has  been  breathed,  in  such  a 
manner  that  no  draught  is  created.  The  most  modern 
are  Tobin's  tubes,  Fischer  and  Stiehl's  tubes  buried  9  or 
10  feet  in  the  gTound,  whereby  air  is  warmed  8°  or  9°  F. 
in  winter  and  cooled  12°  or  13°  F.  in  summer.  Motive 
power  for  the  circulation  of  air  has  of  late  been  obtained 
by  gas  jets,  by  a  jet  of  water  (Messrs.  Verity's  plan),  and 
by  exlioAisting  cowls  and  other  devices. 

To  intercept  the  fuliginous  particles  of  the  air  by 
gauze  curtains ;  to  pass  the  inflowing  air  through  an 
atmosphere  of  spray ;  to  artificially  warm  it  in  winter, 
and  cool  it  in  summer  with  ice :  all  this  preparation  of 
the  air  can  be  carried  out  in  public  buildings  like  the 
Houses  of  Parliament,  but  such  arrangements  are  quite 
impossible  in  the  case  of  the  majority  of  private  houses. 
As  regards  cottages,  the  mere  hint  at  such  a  project  is 
absurd  in  the  extreme. 

An  American  architect  has  expressed  the  opinion-^ 
that  a  building  cannot  be  supplied  with  cool  air  of  a 
pleasant  degree  of  humidity  when  the  external  air  is  hot 
and  damp,  for  the  cooling  would  be  attended  by  the  con- 
densation of  the  moisture  and  the  formation  of  a  mist. 
This  change  cannot,  I  admit,  be  produced  without  a 
preparation  of  the  air  in  underground  chambers  adapted 
for  the  purpose,  such  as  are  available  beneath  public 
buildings  or  large  houses.      In  the  case  of  the  majority  of 

^  "On  tlie  Relation  of  Moisture  in  Air  to  Health  and  Comfort,'-'  by 
Eobert  Briggs,  C.E.,  in  Quarterly  Journal  of  Science,  April  1S7S. 


THE    AIR    OF    OUR    HOUSES  285 

houses,  air,  when  hot  aud  moist,  can  be  passed  through  a 
room  with  greater  rapidity  than  usual,  and  the  occupants 
will  experience  the  cooling  effects  produced  by  the  more 
frequent  renewal  of  air.  The  establishment  of  a  comfort- 
able uniform  loss  of  heat  by  the  body  is  the  point  to  be 
arrived  at  in  our  efforts  to  determine  the  requisite  speed 
for  the  passage  of  the  air. 

Physicians  are  waiting  for  inventors  to  deal  with  this  Eoie  of 
difficult  subject  of  providuig  the  habitations  of  the  people,  is  to*  excite 
poor   as  well   as    rich,   with    some   efficient   and  simple  *^^®  demand 

■*■  _         _  _  _        _  -^        tor  efficient 

ventilating  methods,  remembering  the  above  indispensable  ventilating 
requisites.  There  is  no  difficulty  as  regards  public  a°,ce"^" 
buildings,  such  as  churches,  meeting  halls,  concert  rooms, 
theatres,  ball  rooms,  etc.  They  can  all  be  ventilated  and 
lighted  in  the  same  manner  as  the  House  of  Commons. 
An  exposure  of  the  body,  and  especially  of  that  part  of  it 
named  the  pulmonary  surface,  to  sudden  and  extreme 
ranges  of  temperature,  as  in  coming  out  into  the  cold  air 
from  a  hot,  ill-ventilated  church  or  other  public  building, 
should  be  regarded  as  attended  with  a  certain  amount  of 
risk  to  all,  aud  a  positive  danger  to  the  aged  and  weakly. 

The  role  to  be  played  by  the  Medical  Officer  of  Health 
and  other  sanitarians  in  the  public  interest,  is  to  urge 
Local  Boards  of  Health  to  refuse  to  pass  the  plans  of 
houses  in  which  there  is  no  efficient  pro"\"ision  for  the 
removal  of  used-up  air,  as  well  as  of  other  effete  and 
noxious  matters.  When  a  great  demand  is  in  this  way 
excited,  a  vigorous  attempt  will  be  made  by  those  who 
devote  their  energies  to  the  invention  of  contrivances  for 
our  health  and  comfort  to  supply  that  want. 

The  standard  of  pure  air  for  our  dwellings  and  for  all 
places   of  public   resort,  which  we   should   endeavour   to 
reach,  may  be  considered  to  be  thus  constituted : — 
Active   Oxyqcn,   Ozone,  and  other  ai?'  purifiers,  in   recog-  standard  of 

pui'e  air. 

nizable  quantities. 


286         THE    DELETEPJOUS    EFFECTS    ON    HEALTH    OF 

Organic   Matter,   as   Alhuminoicl   Ammonia,  as  near  '08 

milligram,  per  cubic  metre  as  possible. 
Carbonic  Acid — Not  more  than  "06  per  cent. 
TcmperatiLre  to  be   determined  by  the  sensations  of  the 

majority  as  to  comfort.-^ 
Moisture — Eelative   humidity    70    to    75   per   cent.      A 

difference  between  the  dry  and  wet  bulbs  of  about 

5  or  6  degrees. 
To    approach    this    standard    as    closely   as   possible 
should  be  the  aim  of  all  who  study  the   construction   of 
healthy  homes  for  the  people. 

The  practical  question  arises — How  are  we  to  make 
an  attempt  to  arrive  at  any  point  on  the  road  to  this 
standard  amongst  the  cottages  of  the  poor  ?  The  difficulties 
are  enormous  in  many  cases.  In  the  rural  districts, 
where  the  houses  are  surrounded  generally  by  pure  air 
we  insist  on  every  inmate  (age  not  considered)  having  at 
least  200  cubic  feet  of  air  by  night.  In  tramps'  lodging- 
houses  300  cubic  feet  of  air  in  a  sleeping-room,  and  400 
cubic  feet  in  a  room  used  for  sleeping  and  as  a  day  room, 
are  the  minimum  quantities  sanctioned  by  the  Local 
Government  Board.  In  towns,  where  the  air  is  more  or 
less  impure,  a  larger  quantity  of  air  per  individual  should 
be  insisted  on.  We  should  gradually  aim  at  obtaining 
not  only  the  largest  amount  of  breathing  space  that  is 
practicable,  but  some  efficient  pro^asion  for  the  change  of 
air  to  the  extent  of  from  2000  to  3000  cubic  feet  per 
hour,  or  about  10,000  gallons  of  air  per  head,  per  hour. 

^  The  temperature  of  comfort  of  air  indoors  has  been  variously  stated : — 
55°  to  58°  F.  Hood's  Treatise  on  Warming  Buildings.  59°  F.  Peclet's 
TraiU  de  la  Chaleur.  56°  to  62°  F.  Tredgold's  Princiiiles  of  Warming  and 
Ventilation.  60°  F.  Dr.  Richardson.  62°  F.  Box's  Pra,ctieal  Treatise  on 
Heat.  65°  F.  Reed's  Illustrations  of  the  Theory  and  Practice  of  Ventilation. 
48°  to  60°  F.  Parkes'  Manual  of  Hygiene.  59°  F.  Nurseries  ;  66°  F.  Germrn 
Schools ;  61°  to  64°  F.  Hospitals  ;  66°  to  68°  F.  Theatres  and  Assembly 
Halls. — Morin's  Etudes  sur  la  Ventilation. 


THE    AIR    OF    OUE    HOUSES  287 

How  is  this  to  be  accomplished  ?  HajDpilj,  for  the  sake 
of  ventilation,  the  majority  of  our  cottages  have  an 
abundance  of  chinks  and  crevices  that  admit  air  from 
without.  Fortunately,  also,  a  considerable  change  of  air 
is  effected  through  the  walls  of  our  dwellings,  if  they  are 
composed  of  brick,  or  mud,  or  tufacious  limestone  or  wood. 

Professor  Pettenkofer  has,  by  experiments,  shown  ^  Pemeabii- 
that  through  a  room  made  of  brick  walls,  of  the  capacity 
of  2650  cubic  feet,  every  crack  and  hole  in  which  was 
thoroughly  plugged  up,  1060  cubic  feet  of  fresh  air  passed 
per  hour,  by  virtue  of  the  difference  of  temperature 
(30°  F.)  between  the  outer  (32°  F.)  and  the  inner 
(62°  F.)  air.  He  found  that,  with  a  difference  of 
temperature  of  9^°  F.  between  the  outside  and  the  inside 
of  a  room,  the  spontaneous  ventilation  through  each  square 
yard  of  the  free  wall  amounted  to  about  7  cubic  feet,  or 
43  gallons  per  hour. 

Marker's  and  Schultze's  experiments  on  the  spontaneous 
ventilation  of  stables  confirm  these  observations.  They  dis- 
covered that  with  a  difference  of  temperature  of  9^  F.,  the 
passage  of  air  through  each  square  yard  of  free  wall  was — 


ith  walls  of  Sandstone  . 

4'7  cubic  feet  per  j 

,,           „  Quarried  Limestone 

6-5 

„  Brick 

''J                      !)                          )) 

,,           „  Tufacious  Limestone 

10-1 

„  Mud 

14-4 

All  the  ordinary  building  materials,  such  as  plaster, 
wood,  cement,  etc.,  are  more  or  less  porous,  and  admit  the 
passage  of  air  through  them  in  such  a  manner  that  we 
are  not  conscious  of  the  movement.  We  are  insensible 
to  the  passage  of  air  if  the  velocity  of  the  same  is  less 
than  19  inches  per  second. 

It  will,  perhaps,  be  considered  by  some  that  to  change 
the  air  of  a  cottage  at  the  rate  of  between  2000  to  3000 

^  The  Air,  in  relation  to  Clothing,  Dwelling,  and  Soil. 


288 


THE    DELETERIOUS    EFFECTS    ON    HEALTH    OF 


cubic  feet  per  hour  per  individual,  at  a  velocity,  to  avoid 
draught,  of  less  than  19  inches  per  second,  is  to  supply 
an  enormous  and  unnecessary  amount  of  fresh  air,  and  is, 
moreover,  a  thoroughly  impracticable  project.  Our  con- 
tinental neighbours  do  not  consider  this  amount  excessive, 
if  we  may  judge  from  the  following  table,  given  by  Petten- 
kofer  and  Morin,  of  their  demands  as  to  chano;e  of  air  in 
their  buildings  per  hour  per  person : — 


Hospitals  for  ordinary  cases    . 

2120- 

-2470  cubic 

„       for  wotinded  . 

3530 

„       for  epidemics 

5300 

Prisons         .... 

1766 

"Workshops — ordinary  . 

2120 

„             unhealthy 

3530 

Barracks — day 

1060 

night  . 

1410- 

-1765 

Theatres      .... 

1410- 

~       53                           J3 

Large  rooms  for  long  meetings 

2120 

,,            for  shorter    ,, 

1060 

Scliools  for  adnlts 

880- 

-1060 

„    for  children 

424- 

-  530           „ 

Provided  we  keep  our  walls  dry,  for  then  we  maintain 
them  in  a  porous  condition,  as  moisture  renders  them 
impermeable,  so  long  we  can  draw  a  very  large  quantity 
of  air  through  our  walls,  with  but  little  difference  of 
temperature  between  the  inside  and  outside  of  the  house. 

If  this  spontaneous  ventilation  is  supplemented  by 
some  simple  contrivance,  such  as  a  Tobin's  tube,  a 
Chowne's  tube  or  Hinckes  Bird  arrangement,  which  cannot 
be  interfered  with,  for  admitting  fresh  air  in  so  broken-up 
and  divided  a  state  as  that  its  flow  shall  be  unfelt  by  the 
occupants,  all  that  can  be  done  will  have  been  accom- 
plished for  the  majority  of  our  old  isolated  cottages  in 
the  country  districts,  the  repairs  of  which  often  consume 
the  whole  of  the  yearly  rental.  Pettenkofer  rightly  says, 
"  It  is  a  waste  of  ventilation  if  it  is  directed  against 
avoidable  pollutions  of  the  air  .  .   .  the  proper  domain  of 


THE    AIR    OF    OUE    HOUSES  289 

A'entilation  begins  when  cleanliness  lias  done  its  best." 
We  ought  not,  however,  to  let  matters  rest  here  as  regards 
the  rows  of  cottages  in  our  towns  and  cities,  which  have 
but  little  free  wall  surface,  and  are  often  merely  foul 
caves  with  no  opening  at  the  back  to  allow  of  the  free 
passage  of  air.  Thousands  and  thousands  of  these  urban 
dwellings  of  the  poor  are  caricatures  of  what  cottage 
homes  should  be,  namely,  a  healthful  place  for  rest,  re- 
freshment, and  cheerful  intercourse  after  toil,  and  would 
be  more  truthfully  designated  human  piggeries.  Who  is 
there  amongst  medical  men  that  is  not  familiar  with  the 
appalling  infanticide  that  prevails  amongst  these  districts 
which  have  been  designated  "  Herodian,"  mainly  due  to 
the  foul  air  (for  young  lives  are  the  most  sensitive  tests 
of  the  existence  of  an  infraction  of  sanitary  laws),  and 
partly,  no  doubt,  to  improper  feeding  and  neglect.  That 
noble  appeal  of  Charles  Dickens  for  legislation  for  the 
poor  cannot  but  be  remembered  in  thinking  of  this  sad 
subject :  "  If  those  who  rule  the  destinies  of  nations 
would  but  think  how  hard  it  is  for  the  very  poor  to  have 
engendered  in  their  hearts  that  love  of  home  from  which 
all  domestic  virtues  spring,  when  they  live  in  dense  and 
squalid  masses,  where  social  decency  is  lost,  or  rather 
never  found, — if  they  would  but  turn  aside  from  the 
wide  thoroughfares,  and  great  houses,  and  strive  to  im- 
prove the  wretched  dwellings  in  byeways,  where  only 
230verty  may  walk — many  low  roofs  would  point  more 
truly  to  the  sky  than  the  loftiest  steeple  that  now  rears 
proudly  up  from  the  midst  of  guilt  and  crime  and  horrible 
disease,  to  mock  them  by  its  contrast."  What  a  picture 
was  sketched  of  these  dreadful  places  by  Dr.  Buchanan, 
when  he  was  one  of  the  travelling  inspectors  of  the  Local 
Government  Board  !  "  In  small  closed  courts,  surrounded 
by  high  buildings,  and  approached  by  narrow  and  perhaps 
winding  gangways,  houses  of  the  meanest  sort  stand,  acre 

u 


290  DELETERIOUS    EFFECTS    OF    AIR 

after  acre  of  them,  witli  but  privies  and  dust  bins  to  look 
upon.  And  surely  such  cannot  be  accounted  fit  for  human 
habitation,  while  the  standard  of  that  humanity  is  low. 
Nothing  short  of  a  tornado  can  effectually  ventilate  these 
courts ;  in  still  weather  the  atmosphere  in  them  is  un- 
changed and  unchangeable.  Can  it  be  a  matter  of 
surprise  that  such  regions  should  be  the  favourite  pastures 
or  hunting-grounds  of  filth  diseases,  and  that  moral  as 
well  as  material  deterioration  should  be  invariable  ac- 
companiments ?  It  may  be  truly  said  of  many  evil 
things,  that  '  like  goes  to  like.'  Happily  the  Artisans' 
Dwellings  Bill,  alias  the  Eookeries  Bill,  has  been  passed, 
which  aims  at  the  demolition  of  these  nests  of  disease 
and  crime ;  and  which  will,  it  is  to  be  hoped,  gradually 
diminish  the  most  depraved  and  unhealthy  modes  of  life." 


PART    II 

THE  DETECTIOX    AND  ESTIMATION    OF    THE    AMOUNT    OF    THE 
MOST    IMPORTANT    IMPUEITIES    FOUND    IN    THE    AIR 

T^YO  methods  of  discovering  the  condition  of  the  air,  as 
to  purity,  a  direct  and  an  indirect  one,  have  been  in 
vogue :  the  direct  vfhich  is  either  (a)  chemical,  having  for 
its  object  the  detection  and  estimation  of  the  quantity  of 
impurities,  such  as  the  organic  and  other  solid  bodies, 
and  the  carbonic  acid  present  in  the  air,  or  (h)  biological, 
which  is  concerned  in  the  estimation  of  the  number  of 
germs  present  in  a  known  quantity  of  air ;  and  the 
indirect  one  being  to  ascertain  its  departure  from  a  state 
of  purity  by  the  estimation  of  the  amount  of  ozone  and 
other  purifying  agents  which  have  not  been  used  up  by 
the  organic  matter  and  by  the  various  noxious  gases  with 
which  the  air  is  contaminated. 


DIRECT  METHOD. 


CHAPTEE    XXV 

MODES    OF    OBSEEVING    SOLID    BODIES    IX    THE    AIE,    AND    OF 
SEPAEATIXG    THEM    FOE    EXAMINATION 

Solid  bodies  As  far  back  as  1830,  Ehrenberg  worked  and  published 
m  the  air.  ^^  ^^^^^  subject.  He  showed  the  actual  existence  of  an 
atmospheric  kingdom  of  life,  animal  and  vegetable.  He 
was  followed  by  M.  Gaultier  de  Claubry,  who  passed  air 
from  various  localities  through  water  that  had  been 
exposed  to  a  high  temperature. 

During  the  cholera  epidemic  in  England  of  1849,  the 
dust  of  air  was  much  examined,  in  consequence  of  the 
supposed  discovery  of  certain  bodies  termed  cholera  fungi 
in  infected  air.  M.  Quatrefages,  Pouchet,  Pasteur,  N. 
Joly,  and  Charles  Musset,  Boussingault,  Baudrimont,  and 
Gigot,  are  foreigners  who  have  all  severally  laboured  at 
this  subject  from  different  points,  the  first  five  being 
especially  interested  in  it  in  relation  to  the  doctrine  of 
spontaneous  generation. 

Devergie  examined  the  air  in  the  vicinity  of  a  case  of 
hospital  gangrene,  and  detected  an  enormous  quantity  of 
organic  matter  in  it.  Bits  of  wool,  cotton,  particles  of 
hair,  and  epitheHal  cells  and  starch,  were  most  common. 

In  the  Army  Medical  Pieport  for  1867,  is  an  account 
of  an  experimental  investigation  made  by  Dr.  F.  de 
Chaumont  into    the  ventilation  of  the  new  barracks  at 


SOLID    BODIES   IN    THE    AIR  293 

Chelsea.  He  passed  120  cubic  feet  of  air  tlirongli  a 
freezing  mixture,  and  4*7  c.  c.  of  fluid  condensed  from  it 
contained  epithelium  in  large  amount,  hair  and  various 
fibres,  sand,  soot,  crystalline  substances,  and  chloride  of 
sodium,  together  with  sporangia  of  fungi,  and  monads  in 
considerable  quantity.  In  the  air  of  a  back  yard  of  a 
London  Hospital  he  found  considerable  quantities  of 
epithelium ;  and  in  the  "  dirty  linen  area,"  where  the 
foul  linen  was  kept  in  crates  until  washed,  pus  globules 
and  a  quantity  of  fatty  crystals  apparently  from  dressings, 
bacteria  both  free  and  in  the  zoogiseal  form.  In  the 
Accident  Ward  of  St.  Mary's  Hospital,  Paddington,  he 
discovered  pus  cells  in  the  air  near  some  beds  which  had 
a  bad  reputation  for  erysipelas.-^ 

The  Army  Medical  Eeport  for  1868  contains  similar 
observations  by  Dr.  E.  T.  Wright  on  the  air  of  the 
barrack-room,  Eoyal  Victoria  Hospital,  Netley. 

In  1861  MM.  Eiselt  and  Bechi  published  the  result 
of  some  experiments.  In  the  same  year  an  investigation 
was  undertaken  on  behalf  of  the  Lancet  on  the  dust  of 
town  houses  in  dry  weather.  The  result  of  this  inquiry 
showed  that  it  consisted  of  pulverized  horse  dung,  and 
the  grindings  of  shoe  leather,  and  starch  corpuscles. 

In  1862  Eeveil  and  Chalvet  made  some  observations 
on  the  air  of  the  surgical  wards  of  the  Hospital  of  St. 
Louis. 

Dr.  Jefferies  Wyinan  and  Dr.  Salisbury  were  the 
earliest  of  American  workers  on  atmospheric  dust. 

Samuelson  and  Balbiani  have  also  made  experiments 
on.  this  subject. 

Dr.  Salisbury's  observations  especially  related  to  the 
air  of  the  low  marshy  valleys  of  the  Ohio  and  Mississippi 
in    connection   with   the    causation   of   intermittent   and 

1  "Three  Reports  on  tlie  Sanitary  Condition  of  St.  Mary's  Hospital, 
1875-76." 


294 


MODES    OF    OBSEKVING 


Professor 
Tyndall's 
experi- 
ments. 


remittent  fevers  ^  in  wliicli  he  found  palmelloid  growths. 
M.  Lemaire's  researches,  communicated  to  the  French 
Academy  in  1863,  partly  related  to  marsh  air  in  the 
neighbourhood  of  Sologne,  which  was  a  highly  malarious 
district.  Selmi  and  Balestra  have  both  made  observa- 
tions on  the  air  of  swamps,  and  both  describe  the  presence 
of  myriads  of  spores  of  algge.  The  experiments  of  the 
latter  were  made  on  the  air  of  the  Pontine  marshes. 

A  great  many  examinations  were  made  of  the  dust  of 
the  air  during  the  cattle  plague  epidemic  of  1866.  It 
was  collected  in  most  cases  by  passing  it  through  cotton 
wool.  In  1867,  M.  Poulet  reported  that  he  found  a 
number  of  bacteria  in  the  condensed  vapour  of  the  breath 
in  whooping  cough. 

Tissandier  found  that  atmospheric  dust  contains  from 
25  to  34  per  cent  of  combustible,  and  from  66  to  75  per 
cent  of  incombustible  matter.  He  passed  a  measured 
volume  of  air  through  distilled  water  which  he  evaporated, 
and  then  weighed  the  residue.  In  this  manner,  1  c.  c. 
of  air  yielded — 


In  Paris 


Gramme. 

After  heavy  rain    . 

•006 

After  8  days  of  dry  weather  . 

•023 

Under  normal  conditions 

•007 

Under  normal  conditions 

•00025 

After  lengthened  drouc;ht 

•003 

In  the  country 


A  rough-and-ready  way  of  observing  the  dust  of  air 
is  by  admitting  a  ray  of  sunlight  into  a  darkened  room, 
when  the  "  motes  in  the  sunbeam,"  as  the  particles  of  dust 
have  been  popularly  called,  are  visible  to  us. 

Professor  Tyndall  has  employed  the  very  powerful 
beam  of  the  electric  light  for  the  purpose  of  rendering  the 
dust  of  air  more  apparent,  with  which  he  associated  the 
flame  of  a  spirit  lamp  that  created  an  appearance,  when 
applied  to  the  beam,  of  the  ascent  of  dark  wreaths  of 
^  American  Journal  of  Medical  Sciences,  April  1866. 


SOLID    BODIES    IN    THE    AIR  295 

intensely  black  smoke.  A  large  hydrogen  flame  produced 
the  same  effect.  The  blackness  proved  to  be  due  to  the 
absence  from  the  track  of  the  beam  of  all  matter  capable 
of  scattering  its  light,  which  had  in  fact  been  burnt.  He 
said,  in  his  lecture,  delivered  in  the  Eoyal  Institution  at 
the  end  of  1869  or  commencement  of  1870  : — 

"  Nobody  can  without  repugnance  place  his  mouth  at 
the  illuminated  focus  of  the  electric  beam,  and  inhale  the 
dirt  revealed  there.  Nor  is  the  disgust  abolished  by  the 
reflection,  that,  although  we  do  not  see  the  nastiness,  we 
are  churning  it  in  our  lungs  every  hour  and  minute  of 
our  lives.  If,  after  inspiring  a  quantity  of  common  air, 
a  long  expiration  is  made  through  a  glass  tube  across  the 
electric  beam,  the  luminous  track  is  at  first  uninterrupted. 
The  breath  impresses  on  the  floating  matter  a  transverse 
motion,  but  the  dust  from  the  lungs  makes  good  the 
particles  displaced.  After  a  time,  however,  an  obscure 
disc  appears  upon  the  beam,  and  at  the  end  of  expiration 
the  beam  is,  as  it  were,  pierced  by  an  intensely  black  hole, 
in  which  no  particles  whatever  can  be  discerned.  The 
air  in  fact  has  lodged  its  dirt  in  the  lungs.  A  handful 
of  cotton  wool  placed  over  the  nose  and  mouth  during 
inspiration  makes  the  dark  hole  in  the  beam  of  light 
appear  from  the  beginning  of  expiration.  A  silk  hand- 
kerchief ^  answers  nearly  as  well." 

^  The  old-fashioned  practice  amongst  the  public,  often  witnessed  by 
medical  men,  of  holding  a  handkerchief  to  the  mouth  and  nose  on 
approaching  the  bedside  of  a  person  suffering  from  an  infectious  disease, 
may,  in  the  light  of  recent  investigations,  have  been  a  wise  proceeding, 
and  was  doubtless  intuitively  arrived  at  and  found  by  experience  to  be 
protective  to  the  health.  Sometimes  scents  were  employed,  not  only  in 
the  handkerchief  but  in  the  sick-room  [vide  "Perfumes  and  Ozone,"  in 
Ozone  and  Antozone,  pp.  121,  122).  People  very  commonly  apply  a 
handkerchief  also  to  the  nose  and  mouth  when  they  come  into  contact  with 
a  stench,  to  prevent  the  offensive  odour  from  annoying  them.  The  linen  or 
cotton  fabric  no  doubt  acts  as  an  imperfect  filter,  which  strains  off  the  solid 
particles  floating  in  the  air,  with  which  that  unjileasant  odour  is  associated 


296  MODES    OF    OBSEEVING 

Mr.  C.  Tichborne  communicated  to  the  British 
Association,  in  1870,  an  account  of  his  experiments  on 
the  air  of  Dublin.  Street  dust  he  said,  was  mainly 
composed  of  stable  manure  and  triturated  stones. 

The  dust  of  New  York  has  been  examined  by  the 
New  York  Officers  of  Health  by  exposing  glass  plates  to 
the  air.  The  same  substances  were  present  in  all  of  the 
specimens  ;  street  dust,  particles  of  sand  and  carbon,  fibres 
of  cotton,  fragments  of  vegetable  tissues,  granules  of  starch, 
three  different  kinds  of  pollen  grains,  micro-organisms, 
and  fungal  elements.  The  latter  were  abundant,  ranging 
in  character  from  a  micrococcus  to  mycelial  filaments. 
When  water  was  added  to  the  specimens,  bacteria  and 
vibriones  invariably  made  their  appearance  within  a  few 
hours. 

M.  Miquel  furnishes  the  following  estimate  of  these 
micro-organisms,  which,  as  will  be  seen,  vary  in  number 
in  the  dust  of  different  localities  : — 

No.  of  Bacteria  in  1  gramme  of  dust. 
Observatory  of  Montsouris  near  Paris  .  750,000 

Rue  de  Rennes,  Paris  .  .  .       1,300,000 

Rue  Monge,  Paris      ....       2,100,000 

Mr.  Blackley  -^  has  devoted  his  attention  to  that 
particular  kind  of  air  dust  that  produces  hay  fever, 
namely,  the  pollen  of  certain  kinds  of  grasses.^ 

A  good  account  of  the  great  variety  of  particles  of 
which  atmospheric  dust  is  composed  is  contained  in 
Charles  Eobin's  TraiU  du  Microscope. 

The  space  at  my  disposal  will  not  permit  me  to  enter 

•^  Experimental  Researches  on  the  Causes  and  Nature  of  Catarrhus 
(Estivus,  by  C.  H.  Blackley,  1872. 

^  He  refers  to  one  species,  the  pollen  of  which  is  so  small  that  it  would 
require  37  millions  to  make  a  grain  ;  whilst  6  millions  are  required  of  the 
Particles  of  pollen  of  the  English  meadow  grasses.  He  considers  that 
■^760,  or  the  3427th  part  of  a  grain,  is  capable  of  producing  the  severest 
orni  of  hay  fever. 


SOLID    BODIES    IN    THE   AIR  297 

on  that  very  large  field  as  to  the  presence  of  those  organic  , 
substances  in  air  which  have  in  past  times  fallen  in 
showers^  giving  rise  to  the  belief  that  blood  and  sulphur 
have  descended  from  heaven.  I  must  refer  my  readers 
to  a  little  book,  named  Odd  Showers,  which  is  published 
by  Kerby  and  Son,  of  Oxford  Street,  for  much  interesting 
information  as  to  these  records. 

The  observations  of  Messrs.  Tichborne,  Blackley,  and 
others,  would  lead  one  to  think  that  the  spores  of  fungi 
and  other  light  bodies  are  to  be  detected  in  the  air  at  very 
great  heights,  and  that  they  are  conveyed  by  aerial  currents 
and  storms  from  one  part  of  the  earth  to  another  over 
vast  tracts  of  country. 

The  air  dust,  such  as  we  breathe,  may  be  conveniently 
collected,  for  either  microscopical  or  chemical  examination, 
in  several  ways  : — 

1.  By  means  of  Pouchet's  aeroscope,-^  which  consists  Pouchefs 
of  a  glass  tube  hermetically  closed  at  either  extremity  |jy^®^°®°°P®- 
a  copper  ferule.  The  upper  ferule  is  fixed  to  the  glass, 
and  is  connected  with  a  tube  of  copper,  terminating 
externally  in  a  small  funnel,  and  internally  in  the  inside 
of  the  glass  tube,  in  a  very  finely  drawn  point,  not  more 
than  "5  m.  m.  in  diameter.  The  other  ferule  is  removable, 
and  allows  of  the  introduction  of  a  circular  glass  plate 
into  the  interior  of  the  instrument,  which  is  placed  at 
1  m.  m.  from  the  point  of  the  tube  connected  with  the 
upper  ferule.  This  plate  is  covered  with  adhesive  matter  ; 
and,  if  necessary,  the  point  of  the  tube  is  made  to 
terminate  in  a  minute  perforated  diaphragm  like  the 
rose  of  a  watering  pot,  so  as  to  secure  the  disper- 
sion of  the  atmospheric  particles  over  the  surface  of 
the  plate. 

^  Moyen  de  rassembler  dans  un  espace  infiniment  petit  tons  les  corpuscles 
normalement  invisibles  contenus  dans  uu  volume  d'air  determine. — Comptes 
Ecndus,  T.  i.  p.  748. 


298 


MODES    OF    OBSERVING 


Cunning- 
ham's 
apparatus. 


Dr.  Mad- 
dox's  Aero- 
scope  Pump 


The  apparatus  employed  by  Dr.  D.  D.  Cunningham,'^ 

in  his  numerous  observations 
on  atmospheric  dust,  consists 
of  three  thin  brass  tubes  (A), 
two  of  which  slip  over  the 
third  central  one,  and  come 
into  contact  with  the  opposite 
sides  of  a  projecting  rim  on 
its  circumference.  This  rim 
is  formed  by  the  margin  of  a 
diaphragm,  which  divides  the 
centre  tube  into  two  chambers. 
It  is  of  sufficient  thickness 
to  allow  of  a  spindle  passing 
up  through  it  (B). 
Dr.  Maddox's  Aeroscope  Pump  ^  is  an  improvement 
on  his  aeroconiscope.  It  consists  of  two  metallic 
chambers  A  and  B  screwed  together,  the  chamber  A  being 


/ 

Fig.  20. 
Aeroscope  Pump. 

furnished  with  a  perforated  cone  intended  to  project  the 
dust  of  the  air  on  a  slip  of  glass  covered  with  glycerine. 
This  chamber  is  in  direct  communication  with  the 
chamber  B,  which  contains  an  aspirator.  The  water  passes 
drop  by  drop  by  the  tube  E  into  the  tube  D  which  is  in- 

1  Microscopic  Examination  of  Air,  by  Dr.  D.  D.  Cunningham,  Surgeon, 
H.  M.  Indian  Med.  Service.     Published  by  Government,  1874. 

2  Journal  Microscop.  Socy.,  2d  series,  vol.  i.  p.  338. 


SOLID    BODIES    IN    THE    AIR  299 

clined  at  an  angle  of  45°  with  the  axis  of  the  instrument. 
The  tube  D  is  open  at  its  upper  end,  and  has  a  flute-like 
aperture  laterally  below  the  entrance  of  E.  A  litre  of  water 
is  sufficient  to  pass  6  6  litres  of  air  over  the  glass  slip. 

The  great  objection  to  the  three  foregoing  varieties  of 
the  same  method  is,  that  it  is  difficult  to  obtain  glycerine 
perfectly  free  from  foreign  bodies. 

2.  A  glass  tube  is  heated  to  redness,  and,  when  it 
has  cooled,  is  surrounded  by  a  freezing  mixture.  Air  is 
then  drawn  by  an  aspirator  through  the  tube.  The  great 
cold  condenses  the  moisture  of  the  air,  and  arrests  its 
solid  particles  which  is  in  both  cases  collected  and  exam- 
ined for  nitrogenized  compounds. 

3.  Dr.  Watson  employs  fine  glass  threads  soaked  in 
glycerine  or  powdered  glass,  as  traps  for  catching  the 
solid  substances  which  he  afterwards  washes  with  pure 
water.  Perhaps  the  substance  known  as  glass  wool  would 
prove  a  still  more  effectual  air  filter. 

4.  I  use  a  mineral  named  asbestos,  which  is  a  fibrous 
and  woolly  substance,  composed  of  a  silicate  and  aluminate 
of  magnesia  and  lime,  for  arresting  the  dust  of  the  air. 
A  U-shaped  platinum  tube  about  ^  inch  in  diameter, 
and  7  inches  long,  having  been  filled  at  the  bend  with 
this  inorganic  wool,  and  little  caps  of  fine  platinum 
gauze  being  inserted  at  each  end  of  the  asbestos  to  prevent 
the  loss  of  any  of  its  particles,  a  known  volume  of  air  is 
drawn  through  the  tube  by  means  of  an  aspirator.  The 
tube  loaded  with  asbestos  is  weighed  in  a  delicate  balance, 
both  before  and  after  the  air  is  passed  through  it.^  The 
increase  in  weight,  after  the  experiment,  of  course  indicates 
the  amount  of  solid  particles  contained  in  the  quantity  of 
air  drawn  through  the  tube  by  the  aspirator.  The  plat- 
inum tube  is  then  exposed  to  the  flame  of  a  Bunsen's 
burner,  in  which  it  soon  becomes  red  hot.  When  all  the 
volatile  solid  bodies,  such  as  organic  matter,  nitrates,  etc., 


300  OBSERVING    SOLID    BODIES    IN    THE    AIR 

have  been  burnt  off,  the  tube  ha^dng  been  again  weighed 
is  ready  for  a  fresh  experiment. 

5.  By  taking  the  rain,  which  is  the  great  air  washer, 
and  removing,  by  means  of  a  pipette,  the  solid  particles 
that  subside  in  it  after  a  few  hours'  rest. 

6.  M.  Pasteur  filtered  a  certain  quantity  of  air  through 
perfectly  pure  pyroxyline,  which  is  soluble  in  a  mixture  of 
strong  alcohol  and  ether.  A  tube  containing  a  plug  of 
tliis  material  was  attached  to  a  water  aspirator,  from  the 
exit  portion  of  which  the  amount  of  air  drawn  by  the  in- 
strument per  minute,  can  be  easily  collected  and  measured. 
The  cotton  plug,  on  removal,  was  treated  with  its  solvents, 
and  the  dust  then  allowed  to  subside.  The  complete  removal 
of  the  pyroxyhne  was  effected  by  adding,  and  after  a  time 
remo^dng,  fresh  quantities  of  alcohol  and  ether.  The  dust 
is  then  transferred  to  the  microscope  slide  for  examination. 

7.  M.    Marie-Davy   of  the   Montsouris    Observatory 
collected  the  dust  of  the  air  in  a  receiver  which  was  con- 
nected with  an  aspirator  such  as  is  represented  in  Fig.  21. 
The  receiver  was  composed  of  a  bell  glass,  the 
roughened  lower  edge  of  the  large  opening  of 
which  rests  on  a  piece  of  plate  glass  also  rough- 
ened.     The  upper  and  small  opening  is  closed 
by  a  cork,  which  is  perforated  by  two  glass 
tubes :  one  of  them,  marked  c,  is  connected  with 
the  aspirator ;  the  other,  h,  terminates  at  one 
extremity  in  the  air,  and  at  the  opposite,  within  ^P 
the  bell  glass,  in  a  tapered  point,  a  short  dis-        ^^°-  ^■^" 
tance  from  a  glass  plate  covered  with  glycerine  or  syrup. 

The  arrangements  carried  out  by  ]\i.  ]\iiquel  in  this 
Observatory  for  the  collection  of  the  schizomycetes,  such 
as  the  micrococci,  bacilli,  bacteria,  etc.,  are  most  elaborate 
and  ingenious.  The  latest  and  most  improved  forms  of 
apparatus  will  be  referred  to  in  the  chapter  on  "The 
Biolooical  Examination  of  Air." 


CHAPTEE    XXVI 

MICEOSCOPICAL    EXAMINATION    OF    THE    DUST    OF    THE    AIR 

The  air  contains  sucli  an  immense  variety  of  substances  Dust  de- 
in  the  form  of  dust,  invisible  to  tlie  naked  eye,  tliat  their  animai'^°"^ 
bare  enumeration,  without  entering  into  any  description  vegetable, 

11  -111  u/r-  and  mineial 

01  tliem,  would  occupy  a  considerable  space.  Almute  kingdoms, 
particles  of  anything  and  everything  that  exists  on  the 
earth,  are  liable  to  be  mingled  with  the  air  that  rests  on 
it.  Such  minute  organisms  as  micrococci,  bacteria,  and 
bacilli,  are  omnipresent  except  in  the  pure  air  of  the 
highest  mountains  and  far  away  at  sea.  As  the  air,  in 
which  we  are  always  plunged,  invariably  contains  more 
or  less  of  these  minute  objects,  our  bodies  ^  are  naturally 
invaded  by  the  same.  These  suspended  matters  are 
furnished  by  the  animal,  vegetable,  and  mineral  kingdoms. 

Erom  the  animal  kingdom  is  derived  the  debris  of 
little  creatures  who  have  been  born  and  have  lived  and 
died  in  the  atmosphere,  germs  and  small  eggs. 

From  the  vegetable  kingdom,  spores  of  fungi,  the 
pollen  of  plants  and  seeds  of  all  kinds,  particles  of  finely 
pulverized  straw,  minute  fragments  of  rags,  etc.,  are 
obtained. 

From  the  soil,  dust  of  inorganic  composition,  such  as 
sand,  oxide  of  iron,  lime,  etc.;  from  volcanoes,  sand  and 

^  M.  Lemaire  finds  not  only  in  the  air  that  passes  from  the  lungs,  but 
also  in  the  perspiratory  fluid,  abundant  indications  of  animal  and  vegetable 
life. — CompUs  Eendus,  October  14,  1867. 


302  MICEOSCOPICAL    EXAMINATION    OF 

mud,  and  small  particles  of  carbon ;  from  the  sea,  chloride 
of  sodium  which  is  lifted  by  the  spray  and  conveyed  by 
the  wind  vast  distances  : — are  contributed. 

It  is  in  respect  to  the  dust  and  impurities  in  the  air, 
created  by  man  and  animals,  and  by  vegetation,  in  which 
we  are  at  present  most  interested,  as  they  relate  more 
especially  to  public  health.  Excluding,  then,  a  considera- 
tion of  the  solid  particles  diffused  through  the  air  in  manu- 
factories, and  mines,  to  the  injurious  influence  of  which  so 
many  of  our  fellow-creatures  are  unhappily  exposed,  let 
us  ask  ourselves  the  question  "Wliat  appearances  do  the 
minute  solid  impurities  contained  in  the  air  of  our  dwell- 
ings and  public  buildings,  and  of  our  streets,  present  under 
the  microscope  ?"  Air  dust  has  been  divided  into  the 
light,  which  floats  and  is  wafted  about  by  currents,  and 
the  heavier  particles  that  settle.  The  dust  of  our  houses 
consists  largely  of  light  organic  matter,  either  living  or 
dead,  whilst  that  of  public  buildings  would  appear  to 
contain  a  larger  proportion  of  the  heavier  kinds.  Dr. 
Dust  of  the  -pQYcj  found  that  the   dust  on  the  walls  of  the  British 

British  "^  . 

Museum.  Muscum  cousistcd  of  50  per  cent  of  incombustible 
matter.  The  principal  objects  which  we  see  in  the  dust 
of  rooms  and  hospitals  with  high  powers  are  little  por- 
tions of  (1)  scaly  epithelium  (the  dust  of  the  skin),  (2) 
particles  of  soot,  (3)  small  round  and  oval  cells,  which, 
when  multiplying,  have  an  appearance  like  the  number  8. 
These  little  bodies  have  been  named  "  putrefaction  cells," 
and  by  some  microzymes,  and  have  been  described  by 
Trautman,  Lemaire,  and  Bechamp.  Their  growth  is  accele- 
rated by  hydrogen  sulphide  and  other  vile-smelling  gases, 
and  is  arrested  by  carbolic  acid,  which  is  one  of  our  most 
valuable  disinfectants.  Lemaire  found  them  in  immense 
quantities  in  the  air  of  dirty  prison  cells.  They  belong  to  that 
border  land  which  is  midway  between  the  animal  and 
vegetable  kingdoms.  We  know  not  whether  they  are  animals 


THE    DUST    OF    THE    AIR  303 

or  vegetables.  They  bear  a  strong  reserablance  to  certain 
kinds  of  bacteria  found  in  impure  air  and  water.  These 
organic  impurities  in  air  are  favourite  pastures  for  the 
growth  and  development  of  the  animal  poisons  that  pro- 
duce the  zymotic  diseases,  such  as  typhoid  fever,  scarlet 
fever,  etc.  The  poisons  of  these  diseases  rejoice  and 
luxuriate  iu  filth  of  all  kinds,  especially  in  filthy  air. 
The  spores  of  tricophyton  have  been  collected  in  the 
wards  of  hospitals  devoted  to  skin  diseases,  and  those 
of  achorion  schonleinii  in  wards  containing  cases  of 
favus. 

The  air  of  sick  rooms  and  hospitals  that  are  not 
ventilated  efficiently,  is  loaded  with  organic  impurities, 
which,  in  certain  diseases,  furnish  different  odours, — 
for  example,  a  medical  man  usually  recognizes  the 
presence  of  small-pox  or  rheumatic  fever  in  a  house  by 
their  characteristic  odours.  The  smell  of  a  room  occupied  The  organic 
by  a  person  who  is  suffering   from  abscesses  is  almost  ^p'^'?*'?, 

,      ,         ,  furnished  by 

distinctive  of  this  class  of  malady.  In  smallpox  wards  different 
minute  scales  and  dust  of  dried  pustules,  which,  if  intro-  ^^^^^^'^^-  ■ 
duced  into  the  system  of  one  unprotected  by  vaccination, 
would  reproduce  the  disease,  are  found  floating  in  the  air. 
In  hospitals  devoted  to  skin  diseases,  that  contain  patients 
suffering  from  favus,  ringworm,  etc.,  which  depend  on  the 
growth  in  the  skin  of  little  parasitic  plants  or  fungi,  the 
spores  or  seeds  of  these  plants  may  be  found  suspended 
in  the  air. 

The  air  of  the  streets  and  gardens  of  our  towns  and 
cities  contains  soot,  crystals  of  certain  salts,  starch 
granules,  linen,  cotton  and  wool  fibres,  bits  of  wood,  and 
particles  of  food,  the  hairs  of  man  and  animals  (dogs  and 
cats). 

The  character  of  the  dust  of  the  air  that  is  found 
between  the  pure  air  of  the  country  and  the  impure  air 
of  a  large  city  has  been  well  observed  by  M.  Marie-Davy 


304 


MICEOSCOPICAL    EXAMIXATIOX    OF 


and  liis  associates  at  tlie  Montsouris  Observatory,  in  the 
neiglibourlioocl  of  Paris. 

Bodies  collected  on  glycerine  from  December  30,  1875, 
to  January  2,  1876,   x    1000: — 


Fig.  22. 


1  and  2,  Pollen  ;   3,  Starcli ;  4,  Three  of  these  reddish 
black  bodies  were  attracted  by  the  magnet,  and  are  gran- 


DESCRIPTIOX  OF  PLATE  OF  MICROSCOPIC  OBJECTS  FOUXD 

IN  AIR. 


1.  Pollen. 

2.  Fungi. 

3a.  Starcli  granules. 

3b.  starch  granules  polarized. 

4.  Protococcus  pluvialis. 

5.  Epitlielium. 

6.  Vegetable  spores. 

7.  Spores? 


8.  Fungi? 

9.  Particles  of  soot. 

10.  Crystals  of  chloride  of  sodium. 

11.  Crystals  of  chloride  of  ammonium  ? 

12.  Crystals  of  sulphate  of  soda. 

13.  Mineral  particles. 

14.  Desmids? 


SOLID  E  OD  IE  3  IN  AIR . 
Ic  fdoe  Mye  304- 


THE    DUST    OF    THE    AIR  305 

ules  of  meteoric  iron,  which  have  been  described  by  M. 
Tissandier.  The  fourth  is  a  spore :  it  is  uninfluenced 
by  dilute  sulphuric  acid  which  dissolves  starch  granules. 

M.  Pasteur  suggests  the  institution  of  comparisons 
between  the  kind  and  quantity  of  organized  corpuscles 
disseminated  in  the  air  at  one  place  during  the  several 
seasons  of  the  year  before  and  after  rain,  etc.,  and  at 
different  places  at  the  same  time,  with  the  object  of 
increasing  our  knowledge  of  the  zymotic  diseases,  especi- 
ally when  epidemics  are  prevalent.  He  found  in  the 
winter  months,  during  a  period  of  very  low  temperature, 
ranging  from  15*8°  to  6'8°r.,  that  a  very  small  number 
of  germs  could  be  collected  from  the  air. 

Of  late  years  much  attention  has  been  devoted  by  Micro- 
Koch,  Klein,  Lister,  Klebs,  Sanderson,  and  a  host  of  others,  "'"^sa-msma. 
to  those  constituents  of  the  dust  of  the  air  which  have 
been  denominated  micro-organisms,  and  between  one  and 
two  thousand  publications  have  appeared  in  different 
languages  on  various  branches  of  this  subject.  Into  one 
comparatively  so  new,  with  a  bibliography  so  imposing, 
and  which  is  in  a  state  of  transition  from  month  to  month 
as  new  facts  are  elicited,  it  would  be  unprofitable  in  the 
interests  of  the  health  officer  to  plunge.  It  will  be 
sufficient  to  give :  (1)  an  idea  of  the  appearance^  under 
the  microscope  of  the  more  important  of  these  bodies  ; 
(2)  some  information  as  to  the  number  present  at  different 
times  in  pure  and  impure  air ;  and  (3)  the  reason  for 
prosecuting  researches  into  their  life  history  and  the 
conditions  indispensable  for  the  proof  of  the  existence 
of  a  causative  relation  between  some  of  them  and  certain 
communicable  diseases. 

The  most  approved  and  recent  classification  of  these 

^  A  good  description  of  tliem  is  to  be  found  in  the  Supplement  of  the 
Eleventh  Annual  Report  of  the  Local  Government  Board  for  18S1,  from 
the  pen  of  Dr.  Victor  Horsley. 

X 


306 


MICKOSCOPICAL    EXAMINATION    OF 


scliizomycetes  or  fission-fungi,  named  also  microbes, 
microphytes,  and  micro-organisms,  is  that  of  Zopf  ^  who 
arranges  them  in  four  groups. 

Group  1.  CoccacejE — Genera.   Micrococcus,  Streptococcus  (chain 

coccus),  Sarcina  (packet  coccus)  Merismopedia  and  Asco- 

coccus. 
Group  2.  Bacteriace^ — Genera.   Bacterium,  Spirillum,  Bacillus, 

Vibrio,  Leuconostoc  and  Clostridium. 
Grou^J  3.      LEPTOTRiCHEiE  —  Genera.       Lej)totlirix,      Beggiatoa, 

Crenothrix  and  Phragmidiotlirix. 
Group  4.   Cladotriche^ — Genus.    Cladothrix. 

The  most  interesting  group  is  that  entitled  the  Bacteri- 
aceje  which  contains  the  laro-est  number  of  micro-orsfan- 


r/ 


6  '•• 


e 


h 


\    \  I 


Fig.  23. 


a.  Micrococci  x  600. 

b.  Streptococci  x  600. 

c.  Sareinffi  (packet  cocci)  x  600. 

d.  Bacterium  tei-Dio. 

e.  Bacterium  termo,   diagram  of  outline 

under  higher  power. 
/.   Bacterium  termo,  x  4000  (Dallinger  and 
Drysdale    in    Croolvsliank's    Bacterio- 
logy) -with  flagella. 


g.  Bacillus  anthracis  with  and  without 
spores  X  700. 

h.  Yibrio  serpens  (after  Cohn). 

i.  Spirillum  Obermeieri  (of  relapsing 
fever). 

fc.  Comma-shaped  bacilli  2  (after  Crook- 
shank). 

I.   Bacillus  tuberculosis  with  spores  x  700. 


^  Dr.  Crookshank's  Bacteriology. 

-  There  are  several  varieties  of  comma-shaped  bacilli,  one  kind  being 
found  in  the  mouth  in  connection  with  caries  of  the  teeth  and  another  in 
old  cheese.  The  cholera  comma-bacillus  is  stated  to  be  distinguishable 
from  other  comma-shaped  micro-organisms  by  its  behaviour  under  culti- 
vation. 


THE    DUST    OF    THE    AIK 


107 


isms.  Examples  of  the  most  important  of  its  genera  are 
here  depicted. 

These  micro-organisms  multiply  either  by  division  or 
spore  formation  with  marvellous  rapidity.  Cohn  has 
pointed  out  that  one  bacterium  placed  in  an  organic 
medium  suitable  for  its  growth  will  in  24  hours  have 
developed  16,777,216  bacteria  and  in  three  days 
47  trillions,  but,  that  as  soon  as  they  have  exhausted 
the  nourishment  on  which  they  live,  they  will  soon 
cease  to  exist.  Although  spores  are  more  resisting 
than  the  bacilli  to  extremes  of  cold  and  heat  and 
chemical  agents,  it  is  reassuring  to  learn  that  patho- 
genic organisms  are  less  resistant  to  perchloride  of 
mercury  (our  chief  microbe  destroyer)  than  non-patho- 
genic ones. 

M.  Miquel  has  found  ^  that  the  number  of  bacteria 
varies  much  in  the  air  at  the  different  hours  of  the  day, 


■^  Averages  in  a  cubic  metre  of  air  from  observations  during  6  years. 


Months.                            Park  of  Montsoui 

is. 

Rue  de  Rivoli,  Paris. 

January- 

225 

1880 

February    . 

155 

2480 

March 

495 

3710 

April . 

420 

4905 

May  . 

575 

5750 

June  . 

495 

5535 

July  . 

740 

5205 

August 

6S5 

4405 

September  . 

605 

4615 

October 

500 

38-25 

November  . 

335 

2650 

December  . 

225 

2015 

Annual  Mean 

455                                     3910 

Seasons.                          Pt 

irk  of  Montsouris.                Rue  de  Rivoli,  Paris. 

Winter 

290         ..         .         2690 

Spring 

495        ..         .         5395 

Summer     . 

675         ..         .         4705 

Autumn 

355 

2830 

308 


MICEOSCOPICAL    EXAMINATION    OF 


months  and  seasons  of  the  year,  and  in  the  air  of  different 
localities.^  He  noticed  at  Montsouris,  near  Paris,  two 
minima  between  2  and  3  A.M.  and  between  2  and  3  p.m., 
and  two  maxima  between  7  and  8  a.m.  and  between  7 
and  8  p.m.  They  are  present  in  the  air  in  diminished 
numbers  during  those  atmospheric  states  that  accom- 
pany currents  from  the  south  and  south-west,  viz.,  low 
barometric  pressure,  an  excess  of  moisture  and  purifying 
storms. 


Sea  ail',  Atlantic  Ocean  .... 
Air  of  high  mountains   .... 

,,     the  saloons  of  ships 
Air  at  the  summit  of  the  Pantheon,  Paris 
Air  of  the  city  of  Berne 

,,     new  houses  in  Paris 

,,     the  sewers  of  Paris 

,,     the  Laboratory  of  Montsouris 

,,     old  Parisian  houses 

,,     the  new  Hotel  de  Dieu,  Paris 

,,     the  Hopital  de  la  Pitie 


No.  of  Bacteria 
per  cub,  metre. 

6 


60 

200 

580 

4,500 

6,000 

7,420 

36,000 

40,000 

79,000 


Bacteria  collected  from  1  cubic  metre  of  air. 


Rae 

de 

Rivoli 

750 

970 

1,000 

1,540 

1,400 

960 

990 

1,070 

810 

Although  the  number  of  bacteria  in  the  air  outside  the  hospital  was 
nearly  double  as  much  in  summer  as  in  winter,  the  number  in  the  wards 
was  not  more  than  half  so  numerous  in  the  former  as  during  the  latter 
season,  showing  the  influence  of  open  windows  and  a  fortiori  the  necessity 
of  efficient  ventilation  without  draughts  iu  the  wards  of  an  hospital  at  all 
seasons  of  the  year. 


Hopital  de  la 

Piti6. 

A 

Ward 

Ward 

1881. 

Miction 

Lisfranc 

(men) 

(women) 

March    . 

11,100 

10,700 

April     . 

10,000 

10,200 

May       . 

10,000 

11,400 

June 

4,500 

5,700 

July      . 

5,800 

7,000 

August  . 

5,540 

6,600 

September 

10,500 

8,400 

October 

12,400 

12,700 

November 

15,000 

15,600 

THE    DUST    OF    THE    AIR  309 

Kocli  of  Berlin  -^  and  Klein  of  London  are  assiduous 
in  the  prosecution  of  researches  having  for  their  object 
the  discovery  as  to  whether  a  given  micro-organism  can 
be  demonstrated  to  be  the  cause  of  a  given  disease  in  the 
bodies  of  man  and  animals.  To  obtain  proof  it  is  neces- 
sary to  fulfil  the  following  four  conditions  :  (1)  the  micro- 
organism in  question  should  be  found  in  the  blood  or 
diseased  tissues ;  (2)  successive  cultivations  of  the  micro- 
organism should  be  obtained  in  artificial  media  until  its 
purity  is  undoubted ;  (3)  its  reintroduction  into  the  body 
of  a  healthy  susceptible  animal  should  result  in  the  pro- 
duction of  the  same  disease  as  that  from  which  the  original 
organism  was  primarily  derived  ;  and  (4)  this  same  organ- 
ism should  be  found  in  the  animal  thus  intentionally 
infected.  As  regards  the  diseases  of  man,  each  of  these 
desiderata  has  been  supplied  in  the  case  of  anthrax,  and 
accordingly  ample  proof  has  been  afforded  of  the  existence 
of  an  etiological  relation  between  the  bacillus  anthracis 
and  woolsorters'  disease. 

1  Die  Milzbrand-impfung,  1883. 


CHAPTEE    XXVII 

THE   CHEMICAL   EXAMINATION   OF    AIR 

The  description  of  the  modus  ojijerancli  in  making  sanitary 
estimates  of  the  degree  of  impurity  or  purity  of  tlie  air 
must  necessarily  be  restricted  to  those  bodies  which  are 
tlie  principal  and  universally  observed  injurious  agents, 
to  the  exclusion  of  others,  such  as  sulphuric  and  hydro- 
chloric acids,  arsenic,  etc.,  that  are  the  local  and  special 
products  of  certain  manufacturing  industries. 

Organic  matter  and  carbonic  acid  stand  prominently 
forward  beyond  all  others  as  the  bodies  which  require  our 
attention :  the  former  because  it  is,  if  in  excess,  the 
pabulum  on  wliich  animal  poisons  feed,  amongst  which 
they  increase,  and  through  the  medium  of  which  they 
spread ;  the  latter  because,  whilst  itself  being  noxious  if 
in  any  large  amount,  it  is  nearly  always  in  bad  company. 
Dr.  A.  Carpenter,  in  his  Lectures  on  Preventive  Medicine 
and  PvMic  Hecdth,  writes,  "  Wlierever  you  have  excess  of 
carbonic  acid  from  the  action  of  animal  life,  there  you 
have  also  an  excess  of  other  debris,  such  as  the  organic 
matters  which  pass  off  from  the  respiratory  organs  ;  septic 
matters  given  off  from  the  pulmonary  membrane,  very 
manifest  in  some  diseases  to  the  sense  of  smell ;  impure 
matters  in  the  insensible  perspiration ;  ammoniacal  com- 
pounds from  retrocedent  decompositions — all  of  which  are 
the  most  injurious  of  such  impurities." 

The  presence  of  sulphurous  acid  from  the  combustion 


CHEMICAL   EXAMINATION    OF   AIR  311 

of  coal  in  an  overcrowded  city,  and  free  chlorine  in  the 
air  of  a  manufacturing  centre,  may  certainly  tend  to 
purify  to  some  extent  the  atmosphere,  which  is  so  heavily 
laden  with  animal  emanations.  As  the  existence  in  air 
of  an  excess  of  organic  matter  keeps  the  oxygen,  or  its 
active  form  ozone,  low — for  it  is  always  being  used  up  in 
oxidizing  it — so  the  presence  of  such  intruders  as  sulphur 
or  chlorine  compounds,  takes  the  place  of  this  vitalizing 
gas.  The  purification  of  air  by  disinfectants  after  defile- 
ment reminds  one  of  the  purification  by  filtration  of  the 
water  supply  of  a  town  that  receives  sewage — which  is 
at  the  best  an  imperfect  proceeding,  and,  moreover,  a 
great  waste  of  power.  Far  better  and  wiser  is  it  to  keep 
both  these  media  pure,  rather  than,  after  permitting  them 
to  become  impure,  to  then  expend  force  (money)  in 
endeavouring  to  restore  them  to  a  state  of  purity. 

Dr.  Ballard  and  other  eminent  men  have  diligently 
collected  information  as  to  the  fearful  pollution  of  air 
that  is  unceasingly  proceeding,  and  valuable  materials 
have  been  accumulated  by  a  Eoyal  Commission,  which, 
after  devoting  two  years  to  its  work,  issued  in  1878  its 
recommendations,  in  which  were  embodied  suggestions  for 
the  extension  of  the  Alkali  Acts.  Seven  years  have 
passed  and  matters  are  in  statu  quo  as  to  air  pollution, 
so  that  the  future  presents  a  gloomy  outlook.  The 
scientific  chemist  is  at  length  in  a  position  to  represent  on 
paper,  in  the  form  of  figures,  the  differences  in  the  degree 
of  impurity  of  various  kinds  of  polluted  air.  This  first  step 
towards  the  definite  and  precise  having  been  gained,  it 
then  devolves  on  the  health  officer  to  clearly  lay  down, 
with  exactitude,  the  connection  that  exists  between  these 
degrees  of  impurity  and  certain  forms  of  disease  or  ill 
health.  If  the  scientific  chemist  and  Medical  Officer  of 
Health  can  push  our  knowledge  so  far  as  to  be  able  to 
prove  to  demonstration  that,  if  the  human  body  is  per- 


312  CHEMICAL    EXAMINATION   OF    AIE 

sistently  exposed  to  air  contaminated  by  a  polluting  agent 
to  a  degree  represented  by  a  certain  figure,  it  will  be,  in 
tlie  majority  of  instances,  injuriously  affected,  then  the 
Legislature  will  have  some  basis  on  which  to  work.  A 
Government  would,  whether  in  accordance  or  not  with 
its  own  wish,  be  compelled  to  act  consistently  with  the 
principles  of  past  sanitary  legislation,  the  burden  of  which 
is  that  a  man  shall  do  nothing  which  is  injurious  to  the 
health  of  his  neighbour  or  to  the  public  welfare.  But 
the  obstacles  to  advancement  are  twofold :  first,  an  indis- 
position exists  to  place  further  restrictions  on  trade  which 
is  abeady  depressed ;  and,  secondly,  the  legal  mind  seems 
quite  unable  to  assimilate  the  fact  that  anything  obnoxious 
is  "  a  nuisance  injurious  to  health "  unless  it  creates  a 
definite  disease.  Mr.  Simon  has  tersely  adverted  to  the 
point  thus : — "  To  be  free  from  bodily  discomfort  is  a 
condition  of  health.  If  a  man  gets  up  with  a  headache, 
pro  tcmto  he  is  not  in  good  health ;  if  a  man  gets  up 
unable  to  eat  his  breakfast,  p-o  tanto  he  is  not  in  good 
health.  When  a  man  is  li\dng  in  an  atmosphere  which 
keeps  him  constantly  below  par,  as  many  of  these  trade 
nuisances  do,  all  that  is  an  injury  to  health,  though  not 
a  production  of  what  at  present  could  be  called  a  definite 
disease."  Those  who  govern  cannot  avoid  deploring,  as  do 
the  governed,  that  great  manufactories  that  defile  the  air 
exist,  which  sustain  in  their  vicinity  hundreds  and 
thousands  of  work-people,  whose  vital  energies  are 
lowered  (thus  rendering  them  a  more  ready  prey  to 
disease),  and  whose  offspring  are  stunted  and  depraved 
by  the  medium  which  the  industry  that  supports  them  is 
always  and  needlessly  rendering  unwholesome. 

A.   Organic  Matter. 

Organic  matter  which  is  given  off  from  the  skins  and 
lungs  of  aU  animals,  and  gives  that  peculiar,  indescribable 


CHEMICAL    EXAMINATION    OF    AIR  313 

odour  noticeable  in  ill-ventilated  bedrooms  occupied  by 
many  or  by  dirty  people,  is  very  easily  detected  in  the 
air,  but  there  has  always  been  a  considerable  difficulty  in 
estimating  its  amount,  by  reason  of  the  interference  of 
other  substances  contained  in  air,  which  is  a  mixture 
of  so  many  different  extraneous  bodies. 

Of  the  chemical  composition  of  organic  emanations 
we  know  very  little.  Dr.  Odling  found  that  the  vapours 
arising  from  sewage  were  of  a  carbo-ammoniacal  nature, 
similar  to  such  bodies  as  methylamine,  or  trimethylamine 
and  ethylamine.  Beyond  this  point  there  is  nothing  but 
a  terra  incognita  as  to  this  very  interesting  subject. 

One  of  the  first  processes  adopted  for  the  estimation  Permangan- 

n   ,-1  j_      o  •jj_  j_  ^    !_•        ate  of  Potash 

01  the  amount  oi  organic  matter  was  to  expose  a  solution  j^g^-j^o^j^ 
of  ]3ermanganate  of  potash  to  the  air,  as  the  oyxgen  of  the 
salt  has  a  powerful  oxidizing  effect  on  organic  matters. 
A  burette  was  filled  with  a  very  weak  solution,  and  an 
attempt  was  then  made  to  ascertain  how  much  of  it  was 
necessary  to  drop  into  a  bottle  of  a  certain  capacity, 
before  it  arrived  at  the  point  when  it  was  no  longer 
^gcolorized  by  the  air  of  the  bottle.  The  amount 
necessary  to  reach  this  point  having  been  found,  it  was  a 
matter  of  easy  calculation  to  ascertain  how  much  of  the 
permanganate  of  potash  salt  was  expended. 

Another  plan  was  the  following : — The  test  solution 
is  placed  in  a  bottle  of  known  size,  attached  to  an 
aspirator,  and  is  violently  shaken  with  the  air  in  the 
bottle.  This  air  having  been  washed,  the  bottle  is  re- 
filled by  the  aspirator,  and  a  fresh  quantity  of  air  is 
washed,  etc.,  the  object  being  to  discover  how  much  of 
any  given  sample  of  air  is  necessary  to  c/^ccolorize  the 
pink  solution.  It  will  be  seen  that  in  both  modes  of 
applying  this  permanganate  of  potash  test  the  aim  is  the 
same,  namely,  to  remove  the  pink  colour  of  a  solution  of 
known  strength  by  a  known  quantity  of  air  shaken  with 


314 


CHEMICAL  EXAMINATION    OF    AIR 


it.  It  was  ascertained,  however,  that  the  nitrous  acid 
often  present  in  the  purest  air ;  that  the  sulphurous  acid, 
which  is  very  abundant,  and  the  hydrogen  sulphide  gas, 
which  is  generally  found  in  minute  quantities,  in  town 
air ;  and  the  chlorine  compounds,  which  often  exist  in 
the  air  of  our  manufacturing  cities : — also  decolourize 
permanganate  of  potash.  This  process,  therefore,  never 
unquestionably  proves  the  presence  of  any  organic  matter, 
but  merely  indicates  the  relative  quantities  of  oxidizable 
matter  contained  in  different  samples  of  air. 

Better  modes  have  since  been  de\T.sed,  having  for  their 
object  the  conversion  of  the  organic  matter  of  air  into 
ammonia,  the  amount  of  which  can  easily  be  calculated. 

Water  is  prepared  of 
great  purity  by  distilling  it 
twice  in  perfectly  clean  ves- 
sels. A  definite  quantity, 
generally  50  c.  c,  is  placed 
in  a  Winchester  quart  bottle, 
or  any  other  of  known  capa- 
city. A  little  bellows,^  the 
capacity  of  which  is  ascer- 
tained, with  a  vulcanized 
indiarubber  tube,  is  em- 
ployed for  pumping  fresh 
supplies    of    air    into    the 

tube  attached.  It  possesses  a  valve  at  bottlc,  Or  for  withdrawing 
one  extremity,  which  admits  air  when  ^-}^q  ^ir  Contained  in  the 
air  is  xjumped  into  a  vessel.     If  it  is  j.i     j_  r       i 

wished  to  withdraw  air  from  a  vessel  bottic,  SO  that  irCSh  air  may 
this  aperture  is  closed  by  a  large  cork,    ^.^^gj^    -^^    and  take    itS    pkcC 
B.  A  Winchester  quart  bottle.  ■*- 

(fig.  24). 
The  bottle  and  bellows  are  taken  to  the  place,  the  air 
of  which  it  is  proposed  to  analyze,  and  the  washing  of 

^  Mine  was  procured  at  a  surgical  instrument  maker's,  sucli  as  is  em- 
ployed for  inflating  air-beds. 


Fig.  24. 


A.  Small   hand  -  bellows,    with    indiarubber 


CHEMICAL   EXAMINATION    OF    AIR  315 

the  air  is  proceeded  witli  by  blowing  air  thrice  into,  or 
sucking  air  three  times  out  of,  the  bottle,  replacing  the 
stopper,  and  violently  shaking  the  bottle.  Tliis  perform- 
ance has  to  be  repeated  100  times,  and  is,  as  may  be 
supposed,  sufficiently  laborious.  In  order  to  refill  the 
bottle  with  air,  an  air-pump  is  sometimes  used  until  the 
required  point  is  obtained  on  a  mercury  gauge,  this  being 
found  to  indicate  a  known  amount  of  air,  which  is  then 
allowed  to  enter  in  order  that  it  may  be  washed.  Some 
few,  such  as  Dr.  Angus  Smith,  have  gone  through  a  series 
of  these  air-washings,  and  the  results  arrived  at  ha^'e 
been  found  satisfactory.  The  cumbrousness  of  the 
apparatus,  and  the  labour  involved,  have  been  great 
obstacles  to  the  general  adoption  of  this  process.  Mr.  A. 
Moss'  experiments  on  the  nitrogenous  organic  matter  in 
air,  referred  to  on  page  237,  were  made  by  passing  a 
certam  quantity  of  air,  by  means  of  "  an  accurately 
graduated  aspirator,"  through  four  wash  bottles,  each 
being  of  a  capacity  of  100  c.  c,  and  each  containing  50 
c.  c.  of  pure  distilled  water.  In  the  first  bottle  of  the 
series,  50  c.  c.  of  pure  hydrochloric  acid  were  also 
poured. 

The  air-washings  are  distilled  with  the  caustic  potash 
and  permanganate  of  potash  solution,  and  the  distillates 
are  treated  with  iSJ"essler  reagent.  Although  all  the  or- 
ganic nitrogen  of  the  air  is  not  in  this  manner  converted 
into  ammonia,  that  which  is  most  easily  decomposed,  such 
as  is  theoretically  capable  of  producing  disease,  is  secured. 

A  fourth  method,  which  has  been  suggested  as  appli- 
cable to  the  detection  and  estimation  of  atmospheric 
impurities,  is  to  pass  a  known  quantity  of  air  by  means 
of  a  swivel  aspirator,  graduated  into  cubic  centimetres  or 
cubic  inches,  through  distilled  water  to  catch  the  organic 
matter,  and  through  standard  solutions  of  nitrate  of  sil\^er 
and  chloride  of  barium,  to  retain  respectively  the  chlorine 


316  CHEMICAL    EXAMINATION    OF    AIR 

and  sulphur  compounds.  This  plan  is  perfectly  useless, 
for  the  amounts  of  these  bodies  secured  in  this  way  are 
too  small  for  estimation. 

If  success  is  to  be  achieved  in  air  analysis,  it  is 
absolutely  essential  that  a  very  large  quantity  of  air  be 
washed  in  a  very  small  quantity  of  water,  so  large  indeed 
as  to  be  able  to  obtain  results  which  are  altogether  beyond 
the  reach  of  being  affected  by  the  experimental  errors  that 
are  inseparable  from  all  delicate  analytical  operations. 

A  fifth  method,  already  mentioned  as  adopted  for 
extracting  the  solid  particles  contained  in  air  for  micro- 
scopical examination,  consists  in  drawing  a  measured 
quantity  of  air  by  means  of  an  aspirator  through  a  clean 
curved  tube  (which  has  been  previously  heated  and  cooled), 
surrounded  by  a  freezing  mixture.  The  moisture  contained 
in  the  air  is  condensed,  and  with  it  much  of  the  organic 
matter.  The  tube  is  then  washed  out  with  pure  water 
and  the  washings  are  analyzed. 

The  elaborate  series  of  analytical  observations  on  the 
impurity  of  air  that  have  been  in  progress  for  some  years 
at  the  Montsouris  Observatory,  near  Paris,  under  the 
superintendence  of  M.  Marie -Davy,  and  the  valuable 
analytical  work  on  the  air  of  Glasgow,  that  was  for  a 
short  period  carried  out  by  Mr.  Dixon,  B.Sc,  and  Mr. 
Wm.  Dunnachie,  with  the  co-operation  of  the  Medical 
Officer  of  Health,  are  the  most  complete  and  perfect  that 
have  yet  been  attempted  on  a  large  scale. 

The  arrangements  of  the  latter  gentlemen  are  in  many 
respects  precisely  the  same  as  those  conducted  by  M. 
Marie -Da^y,  with  some  improvements  that  they  have, 
through  the  light  of  English  methods  of  analysis,  made. 

The  apparatus  which  is  used  at  the  Montsouris 
Observatory,  not  only  for  the  estimation  of  the  amount 
of  organic  matter,  but  of  that  of  carbonic  acid,  ozone,  etc., 
consists   essentially   of  two    distinct   parts,  one  being   a 


CHEMICAL    EXAMIXATIOX    OF    AIE 


317 


pump  or  aspirator,  of  a  peculiar  construction,  which  draws 
a  known  quantity  of  the  air  operated  upon  through  a 
certain  solution,  and  the  other  being  an  arrangement  for 
holding  the  absorbing  solution 
and  exposing  it  fully  to  the  in- 
fluence of  the  air. 

The  aspirator  is  composed  of 
a  glass  tube,  about  2  centimetres 
in  diameter,  and  10  centimetres 
long.  This  tube  is  tapered  at 
its  lower  extremity,  which  is 
connected  with  a  vertical  india- 
rubber  or  glass  tube  B,  about  5 
millimetres  in  diameter  and  2 
or  3  metres  in  length.  The 
glass  tube  A  is  closed  at  its 
upper  extremity  by  a  cork, 
tlirough  which  two  tubes  D  and 
C  pass.  The  tube  D  com- 
municates with  a  water  ser^-ice 
pipe ;  a  stopcock  at  the  junction 
serves  to  regulate  the  flow  of 
liquid  which,  running  into  A, 
descends  through  the  ringed 
portion  (h)  of  the  tube  B,  carry- 
ing bubbles  of  air  derived  from 
the  tube  C,  similar  in  appear- 
ance to  the  manner  in  which  the 
mercury  of  a  Sprengel's  pump 
draws  the  au-  (fig.  25). 

The  water  and  air  both  enter  the  displacement  gauge 
E,  where  they  separate.  The  water  flows  away  by  the 
curved  spout  F,  and  the  air  escapes  by  the  tube  G,  which 
terminates  in  an  air  meter  that  measures  its  volume. 
The    "  aspiration    pipe,"    C,    is    attached    to    the    set    of 


Fig.  25. 


318  CHEMICAL   EXAMINATION    OF    AIR 

absorbents  intended  to  remove  the  body  to  be  collected 
from  the  air.  Where,  in  other  analytical  experiments, 
a  larger  quantity  of  air  is  required,  the  observers  at 
Montsouris  combine  together  8  of  these  twisted  tubes, 
arranging  them  in  a  parallel  manner  {vide  fig.  28). 
This  more  powerful  aspirator  delivers  80  litres  of  water 
and  200  litres  of  air  per  hour.  A  set  of  absorbers 
consists  of  two  or  more  elements,  each  element  being 
thus  formed :  A  straight  tube  of  platinum,  1  centimetre 
in  diameter,  and  14  or  15  centimetres  in  length,  open  at 
its  upper  end,  is  dilated  at  its  lower  extremity,  where  it 
is  closed  by  an  arrangement  resembling  the  rose  of  a 
watering  can,  pierced  in  its  centre  by  5  or  6  holes  of 
J  millimetre  in  diameter,  to  facihtate  the  washing  of  the 
tube.  At  the  upper  part  of  the  rose  the  enlarged  portion 
of  the  tube  is  perforated  with  2  0  holes  of  f  of  a  millimetre 
in  diameter,  disposed  in  two  circular  rows.  This  tube  is 
arranged  in  the  axis  of  a  deep  cylindrical  glass,  about  4 
centimetres  in  diameter,  and  11  or  12  centimetres  in 
depth,  named  a  "  barboteur."  Here  it  is  retained  in 
position  by  a  gutta-percha  cork,  which  is  also  traversed 
by  a  bent  glass  tube  of  a  diameter  of  1  centimetre.  If 
we  place  some  water  in  the  glass  and  draw  air  through 
the  bent  tube,  air  wdll  enter  the  platinum,  tube  and 
escape  through  the  liquid  in  the  form  of  numerous  fine 
bubbles  {vide  fig.  27).  Wlien  the  amount  of  organic 
matter  in  the  air  is  sought  to  be  determined,  M.  Marie- 
Davy  and  his  assistants  pass  100  cubic  metres  =  about 
3531^  cubic  feet  of  air,  through  distilled  water,  and 
examine  it  by  the  permanganate  process. 

In  Glasgow,  which  is  well  known  to  be  a  city  of 
smoke  and  manvifactories,  6  or  7  stations  were  established 
in  its  various  parts,  and  one  was  organized  in  pure  air  at 
Eaglesham,  which  is  1 2  miles  distant ;  at  all  of  which 
the  amount  of  ammonia  and  albuminoid  ammonia,  carbonic 


CHEMICAL    EXAMINATION    OF   AIR 


19 


Fig.  26. 


acid,  sulphuric  acid,  and  chlorine,  coupled  with  certain 
meteorological  phenomena,  such  as  rainfall,  temperature, 
etc.,  were  observed. 

Every  station  in  the  city  was  provided 
with  (1)  sets  of  "absorbers,"  each  "set"  or 
"  series  "  being  furnished  with  a  distinct  solu- 
tion containing  glass  beads,  adapted  to  withdraw 
one  of  the  above  named  substances  from  the 
current  of  air  that  passes  through  it;  (2)  a 
water  injection  aspirator  (vide  fig.  26);  (3) 
a  gas  meter  to  measure  the  amount  of  air 
passing  through  the  aspirator  ;  and  (4)  a  water- 
gauge  to  keep  the  aspirators  at  all  the  stations  as 
nearly  as  possible  at  one  and  the  same  speed. 

A  set  of  absorbers  for  free  ammonia  and  albuminoid 
ammonia  {i.e.  the  ammonia  which  we  obtain  by  decom- 
posing nitrogenous  matter),  which 
were  estimated  together  as  nitrogen, 
was  thus  prepared.  The  glasses  hav- 
ing been  thoroughly  washed,  about 
three  ounces  of  glass  beads  {vicle  fig. 
27)  and  some  twice  distilled  water 
were  placed  in  each.  They  were 
allowed  to  remain  in  the  water  for  a 
short  time  in  order  that  any  impuri- 
ties adhering  to  the  beads  might  be 
removed  by  the  water.  The  distilled 
water  having  been  poured  off,  1 0  c.  c, 
of  diluted  sulphuric  acid,  and  70  c.  c. 
of  distilled  water,  free  from 
monia,  were  introduced  in  the  fol 
lowing  proportions  : — 

Dilute  Sulphuric  Acid.  Distilled  Water.  Glass. 

5  c.  c.  .  .          30  c.  c.  in  No.  1 

3  c.  c.  .  .          30  c.  c.  „  „     2 

2  c.  c.  .  .          10  c.  c.  „  „     3 


(r^    A  set  of 
Absorbers 


Fig.  27. 
A  Set  of  Absorbees. 
a  a  a.    Tubes  with  roses  at 
am-  their  extremities. 

6  6  6.    Absorbing  solutions, 
c  c.     Indiarubber    tube    con- 
nections. 


320 


CHEMICAL    EXAMINATION    OF    AIR 


The  roses  being  inserted,  the  set  of  absorbers  was 
attached  to  an  aspirator  for  48  hours,  in  which  space  of 
time  about  200  cubic  feet  of  air  had  passed  through  this 
dilute  sulphuric  acid.  At  the  end  of  this  time  the 
contents  of  the  glasses,  beads  included,  were  poured  into 
a  copper  flask  made  out  of  a  very  large  ball-cock,  into 
which  15  c.  c.  of  a  solution  of  carbonate  of  potash  (240 
grammes  in  a  litre  of  distilled  water)  had  been  previously 
poured.  The  washings  with  twice  distilled  water  of  the 
glasses  and  tubes  were  added,  so  as  altogether  to  just 
exceed  ^  htre.  The  copper  flask  was  then  attached  to  a 
condenser,  and  distillation  was  performed  exactly  as  has 
been  described  on  pages  40  to  48,  in  the  analysis  of 
water,  the  first  ^  litre  yielding  the  ammonia,  and  the 
remaining  -}  litre,  after  the  addition  of  50  c.  c.  of  the 
caustic  potash  and  permanganate  of  potash  solution, 
furnishing  the  albuminoid  ammonia ;  the  amount  in  each 
case  being  estimated  by  a  standard  ammonia  solution 
precisely  as  has  been  there  indicated. 

I  am  not  aware  that  beads  are 
employed  at  the  Montsouris  Obser- 
vatory for  minutely  subdividing  the 
streams  of  air.  This  addition  has 
been  made,  I  believe,  by  Mr.  Dixon 
(vide  fig.  27).  And  to  it  is  partly, 
in  all  probability,  to  be  ascribed  the 
higlier  results  which  he  obtains. 

At  the  station  at  Eagiesham  he 
used  an  aspirator  formed  of  a  combina- 
tion of  twisted  tubes,  the  internal  orifice 
of  each  having  a  slit  {vide  fig.  28). 

There  are  a  great  variety  of  as- 
pirators, and  it  is  difdcult  to  decide 
as  to  which  is  the  best  form.  Some  are  more  adapted  for 
certain    purposes    than    for    others.       Descriptions    and 


Fig.  28. 


CHEMICAL    EXAMINATION    OF   AIR 


121 


sketches  of  many  of  the  favourite  kinds  are  to  be  found  in 
Ozone  and  Antozone,  pp.  250-259. 

The  improvements  effected  by  Mr,  Dunnachie  on  the 
retirement  of  Mr.  Dixon  consisted  in  employing  more 
"  absorbers  "  in  each  "  series,"  in  substituting  glass  retorts 
for  the  copper  flasks,  and  in  abolishing  the  error  attendant 
on  the  changes  in  the  water  pressure  by  adapting 
Borradaile's  governors  for  street  lamps  to  the  meters. 

There  would  seem  to  be  some  divergence  in  the  results 
as  derived  by  the  bellows  pump  and  shaking  (described 
on  page  314)  when  compared  with  those  procured  by 
aspiration  with  rose-ended  tubes.""- 


*> 

By  Shaking.                  Aspiration,  3  bottles. 

Milligramme  in  1  Cubic  Metre  of  Air. 

Free 
Ammonia. 

Alb. 
Ammonia. 

Free 
Ammonia. 

Alb. 
Ammonia. 

Manchester,  Dec.  2, 1876, 
dull,  clamp  morning    . 

Ditto,  Dec.  4,  raining    . 

•093 

•160 
•159 

•070 

•053 

•124 

Prof.  Ira  Eemsen  has  adopted"  as  a  collector  of  the  Prof, 
organic  matter  of  air  a  modification  of  Chapman's  ^^™®J^"^^ 
arrangement  of  a  funnel  filled  with  pumice  stone.  A 
tube  of  |-th  inch  internal  diameter  and  from  5  to  7  inches 
long  is  drawn  out  at  the  lower  end,  so  as  to  accommodate 
a  small  piece  of  rubber  tubing.  Having  been  carefully 
washed  it  is  filled  with  ignited  ]Dumice  stone.  A  piece  of 
platinum  gauze  having  first  been  dropped  into  the  tube,  a 
layer  of  coarsely  powdered  pumice  stone  is  introduced,  and 
finally  a  layer  of  the  finely  powdered  material  is  placed 
on  the  coarse  layer.  10  litres  of  the  air  to  be  examined 
are   drawn   through   this   tube   of  pumice    stone   by   an 

1  Proc.  of  Rotjal  Society,  December  13,  1877. 

2  "  Organic  matter  in  the  Air,"  in  National  Board  of  Health  Bulletin, 
January  31,  1880. 


322 


CHEMICAL    EXAMINATION    OF    AIR 


Mr.  A.  H. 

Smee's 
Metliod. 


Pulveriza- 
tion of  water 
Method. 


aspirator.  The  organic  matter  obtained  is  examined 
by  the  Wanklyn^  Chapman,  and  Smith  process,  and  its 
amount  is  determined  by  means  of  the  Nessler  reagent. 
No  ammonia  is  obtainable  from  absorbents  placed  be- 
tween the  pumice  stone  tube  and  the  aspirator.  The 
pumice  stone  requires  to  be  freshly  ignited  after  each 
experiment. 

The  organic  matter  has  been  obtained  for  examination 
from  air,  by  collecting  the  moisture  that  is  seen  to  attach 
itself  to  the  walls  and  windows  of 
crowded,  ill- ventilated  halls,  which  has 
been  condensed  by  the  cold  air  outside. 
Mr.  A.  H.  Smee  ^  employs  a  glass 
funnel  drawn  to  a  point,  and  filled 
with  fragments  of  ice.  The  aqueous 
vapour  in  the  air  is  deposited  as  a 
dew  on  the  sides  of  the  funnel, 
which  runs  down  and  is  received 
in  a  vessel  underneath.  This  air 
moisture,  in  whatever  way  procured, 
is  examined  for  nitrogenous  com- 
pounds. 

The  process,  which  will  now  be  described,  is  preferred 
by  me  to  all  that  have  yet  been  adverted  to  : — 

1.  Because  it  is  the  most  rapid  and  reliable  one  that 

has  been  devised. 

2.  Because    the    air- washing    apparatus    required    is 

portable,    and    can    be   readily   carried  in    the 

hand  by  any  one  in  a  small  box. 
It  consists  in  bringing  continually  fresh  quantities  of 
air  into  intimate  contact  with  a  small  quantity  of  very 
pure  water,  which  is  reduced  to  a  minute  state  of  sub- 
division by  pulverization.  The  tools  required  are  the 
following  : — 


Fig.  29. 


^  Soc.  Science  Transccctions,  1875,  p.  486. 


CHEMICAL    EXAMINATION    OF    AIR 


?.  9  ?. 


1.  A  glass  cylinder  about  7-^  or  8  inclies  long  and  2 
inches  in  diameter,  furnished  with  a  large  black  india- 
rubber  stopper,  perforated  with  two  holes,  into  one  of 
which  the  air -pipe  of  a  Bergson'e  spray  producer  is  fitted, 
the  other  being  intended  for  the  passage  of  a  straight  glass 
tube  about  12  inches  long  and  ^  inch  in  diameter. 


Fig.  30. 

A.  Cylinder.  E.  Black    indiarubher   cork,    thron^li 

,    B  B.  Wash-bottles.  which  jiasses  the  air-pipe  of  a  Bergson's 

0.  Black  indiarubber  ball  pump.  spray  producer  and  a  straight  glass  tube, 

D.  Black  indiarubber  J  oz.  ball,  to  which  one  eud  of  which  stoppers  into  a  wash- 

a  glass  tube,  tapered  to  a  fine  point,  is  bottle, 

attached.  P.  Level  of  fluid  in  cylinder. 

2.  Two  stoppered  Woulff' s  wash-bottles,  of  a  capacity 
of  about  130  c.  c. 

No  corks  should  be  employed  for  connections.  The 
tubes  are  stoppered  into  the  necks  of  the  wash- 
bottles. 

3.  A   stoppered   flask,  of  the  capacity  of   100   c.  c, 
with  a  mark  at  about  70  c.  c. 

4.  A  black  -1-  oz.  indiarubber  ball,  to  which  a  glass 
tube,   drawn  to   a  fine  point   at  its   extremity,  is  fitted. 


324  CHEMICAL   EXAMINATION    OF   AIR 

The  point  is  protected  bj  a  cap  formed  of  an  inch  of  the 
smallest  black  indiarubber  tubing,  sealed  at  one  end. 

The  steps  of  the  process  are  as  follows  : — 

The  several  .parts  of  the  apparatus  having  been 
thoroughly  cleansed  in  the  laboratory  with  twice-distilled 
water,  which  gives  no  colour  whatever  with  ISTessler  test, 
by  the  aid  of  the  ball  injection  tube,  the  several  parts  are 
securely  attached  to  one  another.  The  cylinder  with  its 
spray  producer,  the  wash-bottles,  the  ball  pump,  and  flask 
filled  up  to  the  70  c.  c.  mark  with  twice-distilled  water, 
are  packed  in  a  small  practically  air-tight  box,  and 
conveyed  to  the  place,  be  it  a  public  building  or  a  private 
dwelling-house,  or  some  marsh  land,  where  it  is  intended 
to  make  an  air-washing. 

Pour  a  little  of  the  70  c.  c.  of  the  distilled  water 
contained  in  the  flask  into  the  glass  cylinder,  so  that 
when  inverted  its  level  may  be  just  below  the  jets  of  the 
spray  tubes.  The  remainder  of  the  70  c.  c.  is  poured  in 
about  equal  proportions  into  the  two  wash-bottles. 

Air  should  then  be  pumped  into  the  glass  cylinder  so 
as  to  produce  in  its  interior  a  fine  spray  or  mist  by  means 
of  the  indiarubber  pump,  the  capacity  of  which  should 
have  been  previously  ascertained  by  the  help  of  an  air  or 
gas  meter.  The  gTeater  part  of  the  spray  returns  to  the 
water  at  the  bottom  of  the  cylinder  to  be  reconverted 
into  spray  with  fresh  portions  of  air,  but  a  small  quantity 
passes  downwards  through  the  straight  tube  into  the  wash- 
bottle  to  which  it  is  attached,  and  a  still  smaller  portion 
reaches  the  other  wash-bottle.  At  the  exit  tube  of  the 
latter  no  spray  can  be  perceived.  The  indiarubber  pump 
which  I  employ  delivers  3 '2  cubic  inches  of  air  every 
time  its  sides  are  approximated  by  the  pressure  of  the 
hand,  so  that  if  it  is  emptied  540  times,  an  operation  which 
altogether  consumes  about  a  quarter  of  an  hour,  1  cubic  foot 
of  air  is  injected  into  the  glass  cylinder.      At  the  termina- 


CHEMICAL    EXAMIXATIOX    OF    AIK  325 

tion  of  the  stage  of  air-wasliing,  the  distilled  water  in  the 
cylinder  and  in  the  wash-bottles  should  be  immediately 
poured  back  into  the  flask,  and  the  apparatus  having  been 
restored  to  the  box  is  returned  to  the  laboratory ;  where 
the  interior  of  the  cylinder,  and  wash-bottles,  and  glass 
tubes,  should  be  at  once  washed  out,  by  the  aid  of  the 
ball  injection  tube,  with  twice  distilled  water.  The  great 
point  to  be  aimed  at  is  to  wash  the  several  parts  of  the 
apparatus  most  thoroughly  with  as  little  distilled  water  as 
possible,  as  if  indeed  this  fluid  was  most  costly.  The 
washing  of  the  apparatus  can  efficiently  be  accomplished 
with  30  c.  c,  which  should  be  poured  also  into  the  flask, 
thus  filling  it  up  to  its  100  c.  c.  mark. 

The  mere  washing  of  the  apparatus  with  distilled 
water  both  before  and  after  the  operation  is  sufficient  to 
heighten  the  experimental  error,  which  is  inseparable  from 
all  these  delicate  experiments.  Accordingly,  it  is  necessary 
to  know  the  average  amount  of  nitrogen,  whether  in  the 
form  of  free  ammonia  or  albuminoid  ammonia  {i.e.  the 
ammonia  which  we  obtain  by  decomposing  nitrogenous 
matters),  which  is  present  in  the  air  in  which  these 
cleansings  are  made.  If  we  know  the  average  experi- 
mental error  which  occurs  when  blank  experiments  are 
made  in  our  laboratory,  there  is  nothing  easier  than  to 
make  the  necessary  deduction  from  the  results  furnished 
by  an  au'-washing.  The  average  experimental  error  of 
manipulation  when  the  preliminary  and  terminal  cleansings 
of  the  apparatus  are  made  in  my  laboratory  is  about  '006 
of  albuminoid  ammonia  for  a  cubic  foot  of  air,  a  Cjuantity 
which  is  consequently  always  deducted  by  me  from  any 
result  obtained  from  an  air  analysis. 

The  contents  of  the  flask,  namely,  the  air- washings  and 
the  cleansings  of  the  cylinder  and  wash-bottles,  are  analyzed 
for  ammonia  and  albuminoid  ammonia  in  a  manner  pre- 
cisely similar  to  the  mode  adopted  in  a  water  analysis. 


326 


CHEMICAL    EXAMINATION    OF    AIR 


A  small  stoppered  retort,  of  a  capacity  of  200  c.  c. 
connected  with  a  glass  Liebig's  condenser,  about  18 
inches  long,  is  necessary. 

By  means  of  a  little  copper  basin,  containing  sand  or 
oil,  placed  on  a  large  ring  of  a  retort  stand,  heat  can  be 
applied  more  gently  than  with  a  naked  flame.  I  often, 
however,  use  the  naked  flame  with  the  chimney,  as  figured 
on  page  115.  The  retort,  condenser,  etc.,  should,  after 
copious  ablutions  with  tap  water,  be  first  thoroughly 
washed  internally  by  distilling  through  the  apparatus  some 
twice-distilled  water.  The  100  c.  c.  of  air- washings 
contained  in  the  flask  should  then  be  introduced  into  the 
retort,  and  distillation  begun. 

A  dozen  test  glasses  that  will  stand  without  support, 
about  4  inches  long,  and  4th  inch  in  diameter,  the  bases  of 


Fig.  31. 


which  have  no  colour,  should  have  been  previously  marked 
with  a  file  at  the  height  which  is  reached  by  10  c.  c.  of 
fluid.  'No  corks  should  be  used.  The  retort  and  con- 
denser can  be  united  by  a  packing  made  of  a  strip 
of  common  writing-paper.  The  first  distillate  of  10  c.  c. 
that  passes  over  should  be  Nesslerized  by  introducing  into 
it  -J-  c.  c.  of  Nessler  reagent,  and  shaking  the  mixture. 
We  should  not  blow  into  the  pipette  so  as  to  mingle  the 
contents  of  the  ISTessler  glass,  as  is  not  uncommon  in 
water  analysis.      The  second,  third,  and  fourth  distillates. 


CHEMICAL    EXAMINATION    OF    AIR  327 

each  of  10  c.  c,  may  be  thrown  away,  and  a  thhd  of  the 
quantity  of  ammonia  found  in  the  first  distillate  be  added 
as  in  water  analysis,  page  42.  The  contents  of  the  retort 
are  then  to  be  allowed  to  cool.  After  it  has  become 
reduced  to  a  state  of  tepidity,  10  c.  c.  of  the  solution  of 
permanganate  of  potash  and  caustic  potash  are  added,  and 
the  distillation  again  proceeded  with.  Each  of  the  three 
distillates  should  be  tested  with  ^  c.  c.  of  Nessler  reagent, 
and  then  the  estimation  of  the  coloration  of  the  single 
ammonia  distillate,  and  the  three  albuminoid  ammonia 
distillates,  should  be  made. 

A  burette  with  the  subdivisions  of  each  cubic  cen- 
timetre widely  apart  is  necessary.  Mine  is  1  foot  long 
and  xoth  inch  in  diameter,  and  with  it  y^ths  of  a  c.  c. 
can  easily  be  read. 

The  very  dilute  standard  ammonia  solution  used  is 
half  the  strength  of  that  found  most  convenient  in  water 
analysis,  and  is  prepared  by  mixing  5  c  c.  of  the  strong 
standard  solution  of  ammonia  (1  milligramme  of  ammonia 
in  1  c.  c.)  with  995  c.  c.  of  twice-distilled  water. 
Accordingly 

1  c.  c.  of  it  contains  "005  milligramme  of  ammonia. 

ic.  c.      „     -0025  .,  „  „    ; 

j\c.  c.      „     -0015 
xVc-c.      „     -0005 

It  is  necessary  to  make  up  standards  exactly  as  in 
water  analysis.  The  test  glasses  should  be  cleansed  with 
twice-distilled  water  by  the  aid  of  the  pipette  before  they 
are  employed.  If  Gmelin's  wash-bottle  is  used,  organic 
impurities  from  the  breath  may  be  introduced. 

The  test  glasses  containing  the  standards  and  the 
distillates,  the  colour  of  which  it  is  necessary  to  imitate, 
are  placed  on  a  sheet  of  white  paper.  It  is  often  very 
convenient  to  stand  them  in  a  common  test  tube  rack. 
The  differences  between  the  tints  of  each  -J^th  of  a  c.  c. 


.S28  CHEMICAL    EXAI^IIXATION    OF    AIR 

of  the  very  dilute  standard  ammonia  solution  are  dis- 
tinguished with  great  precision  by  one  who  has  had  some 
practice  with  these  delicate  analytical  operations. 

The  great  objection  to  the  employment  of  so  small  a 
quantity  of  air  as  1  cubic  foot  is,  that  the  experimental 
error  falls  so  heavily  on  the  results.  This  difficulty  can  be 
overcome  by  practice  and  the  gTcatest  attention  to  cleanli- 
ness, and  the  minute  details  with  which  every  practical 
scientific  chemist  is  conversant.  Blank  experiments  on 
pure  air,  or  on  the  twice-distilled  water  with  which  the 
apparatus  is  washed,  will  give  confidence  to  the  operator 
in  his  tools,  and  by  affording  liun  practice  will  help  him  to 
obtain  reliable  results  from  air  of  different  degrees  of 
impurity. 

Whichever  of  the  foregoing  plans  be  adopted  for 
extracting  the  organic  matter  from  the  air,  its  washings 
are  treated  in  the  same  way.  These  washings  are 
examined  by  the  AYanklyn,  Chapman,  and  Smith  process, 
in  a  manner  precisely  similar  to  the  mode  in  which  the 
organic  matter  contained  in  water  is  detected  and  estimated, 
which  has  already  been  described  {vide  page  39). 

B.   Carljonic  Acid. 

Carbonic  As  I  bcforc  statcd,   carbouic  acid   is   not   the  worst 

impurity  in  the  air  of  our  houses,  for  it  stands  second  to 
the  organic  matter  in  its  evil  effects,  yet  an  estimation  of 
its  amount  is  an  index  of  the  foulness  of  air  of  a  very 
valuable  kind.  There  are  several  modes  of  detecting  its 
presence  and  calculating  its  amount  in  any  given  sample 
of  air. 
Petten-  The  method  known  as  Pettenkofer's  is  a  good  one, 

Method.  hut  requires  the  expenditure  of  much  time  and  labour. 
It  consists  essentially  in  washing  a  certain  measured 
quantity  of  air  with  a  definite  quantity  of  hme  water  or 


CHEMICAL    EXAMINATION    OF   AIR  329 

baryta  water,  and  noting  the  loss  of  causticity  that  either 
of  these  waters  has  undergone ;  in  other  words,  the 
amount  of  hme  or  baryta  that  has  united  with  tlie 
carbonic  acid.  The  causticity  of  tlie  lime  water  to  be 
used  in  the  experiment  is  first  ascertained  by  mixing 
with  a  certain  measured  quantity  of  it  a  known  amount 
of  a  solution  of  oxalic  acid  to  neutralize  it.  The  oxalic 
acid  solution  is  made  of  such  a  strength,  2*25  grammes 
in  1  litre  of  water,  that  1  c.  c.  will  exactly  neutralize  1 
milligramme  of  hme.  Turmeric  paper  is  employed  for 
noting  the  exact  point  of  neutralization.  The  same 
quantity  of  lime  water  is  placed  in  the  bottle  of  air  to 
be  examined,  is  shaken  with  it,  and  is  allowed  to  remain 
in  it  for  not  less  than  six  or  eight  hours,  at  the  end  of 
which  time  the  causticity  of  the  lime  water  is  again 
determined  by  means  of  the  oxalic  acid  solution.  The 
difference  will  furnish  us  with  the  amount  of  lime  that 
has  become  imited  with  carbonic  acid  in  the  measured 
amount  of  air  under  examination.  From  this  datum  the 
pei]centage  of  carbonic  acid  is  easily  calculated.  Correc- 
tions have  to  be  made  for  temperature  and  barometric 
pressure.  This  process  is  fully  described  in  Parkes' 
Hygiene  (fifth  edition). 

The  determinations  of  the  amount  of  carbonic  acid  in  The 
the  air  are  thus  made  at  the   Montsouris    Observatory,  observatory 
A    set    of    absorbers,    consisting    of    four    elements    or^^^tiiod. 
"  barboteurs,"  each  of  course  furnished  with  its  platinum 
rose,  is  charged  with  a  20   per  cent  solution  of  potash, 
coloured  blue  with  a  few  drops  of  litmus.      The  elements 
are  connected  with  one  another,  all  being  in  communication 
with  the  aspirator  depicted  in  Eig.  25. 

The  last  element  serves  to  show  if  all  the  carbonic  acid 
has  been  extracted  by  the  preceding  ones.  After  the 
passage  of  100  cubic  metres  of  air  the  contents  of  each 
element   is   submitted   to    analysis.      The  platinum  tube 


330 


CHEMICAL    EXAMINATION    OF    AIR 


throngli  which  the  air  has  entered  is  attached  to  a 
graduated  burette  containing  hydrochloric  acid.  The 
glass  tube  through  which  the  air  has  passed  out  is  con- 
nected with  a  cylindrical  displacement  receiver  full  of 
water,  covered  with  a  layer  of  petroleum  oil,  to  prevent 
the  water  from  dissolving  the  gas,  and  furnished  with  an 


A.  Graduated  'burette. 

B.  An  element  or  "barboteur. 

C.  Indiarubber  tube. 


D.  Displacement  vessel. 

E.  Bent  tube. 

F.  Measure. 


exit  tube.  This  exit  tube  E  may  be  inclined  on  one 
side  in  such  a  manner  that  its  upper  end  shall  be  on  a 
level  with  the  liquid  in  T>.  A  defiuite  quantity  of 
hydrochloric  acid  is  allowed  to  flow  into  the  solution  of 
potash,  sufficient,  indeed,  to  convert  the  blue  colour  of  the 
litmus  to  a  red  tint.      The  carbonic  acid  evolved  displaces 


CHEMICAL    EXAMINATION    OF    AIR  331 

a  volume  of  the  water   equal  to  itself.      This  water  is 
received  into  a  burette  graduated  into  cubic  centimetres. 

The  method  pursued  at  Glasgow  by  Mr.  Dixon,  con- 
sisted of  the  i^assage  of  1  cubic  foot  of  air  per  hour,  for 
48  hours,  through  solutions  of  caustic  potash  (320 
grammes  per  litre)  contained  in  three  wash-bottles  (a  set 
of  absorbers).  On  their  removal  to  the  laboratory,  the 
carbonic  acid  was  precipitated  as  carbonate  of  baryta, 
which  was  allowed  to  subside  in  well-stoppered  bottles, 
and  the  amount  of  carbonic  acid  was  estimated  by  the 
sp.  gr.  process.  Dr.  A.  Smith  has  found  ^  that  three 
washing-bottles  containing  a  solution  of  barium  hydrate, 
were  insufficient  to  absorb  all  of  the  carbonic  acid  from 
the  air  aspirated  through  them. 


Volumes, 

COo 

per  million  volumes 

;  of  air. 

Exp.  5. 

Exp.  6. 

1st  bottle 

gave 

80 

115 

2d 

62 

71 

3cl 

62 

66 

4th 

53 

62 

5  th 

18 

62 

6  th 

45 

62 

Total     .      320  438  in  series  of  6  bottles. 

Another  good  method,  proposed  by  Wanklyn,  based  wankiyn-s 
on  the  same  principle,  is  to  make  a  standard  by  dis- 
solving 4'74  grammes  of  dried  carbonate  of  soda  in 
1  litre  of  water  —  a  solution  which  contains  a  cubic 
centimetre  of  carbonic  acid  (=rl-97  milligrammes  of 
carbonic  acid)  in  every  cub.  cent,  of  liquid. 

A  bottle  capable  of  holding  2000  cubic  centimetres 
of  air,  or,  failing  one  of  exactly  the  right  capacity,  a 
stoppered  Winchester  quart  bottle,  having  been  washed 
clean,  is  rinsed  with  distilled  water  and  allowed  to 
drain.  It  is  filled  with  the  air  to  be  tested  by  sucking 
1  Proc.  of  Royal  Society ,  December  13,  1877. 


332  CHEMICAL    EXAMINATION    OF    AIR 

out  the  air  of  the  bottle  with  a  glass  tube,  or  with  a 
bellows,  like  that  in  Fig.  24,  when  air  from  without 
immediately  takes  its  place.  100  c.  c.  of  baryta  water 
are  introduced,  and  the  bottle  is  shaken  for  two  or 
three  minutes.  The  baryta  water,  on  being  poured  out 
into  a  glass  cylinder,  is  found  to  be  more  or  less  turbid, 
being  slightly  so  if  the  air  is  good,  and  like  milk  if  it  is 
very  impure.  We  then  proceed  to  imitate  the  degree  of 
turbidity  in  the  following  manner:- — The  standard  soda  solu- 
tion is  measured  by  drawing  out  the  number  of  cub.  cents, 
required  from  a  burette  graduated  to  deliver  tenths  of  a 
cubic  cent,  of  solution.  We  take  100  c.  c.  of  baryta 
water  and  introduce  into  it  1  c.  c.  of  soda  solution.  If 
the  turbidity  thus  occasioned  is  about  equal  to  the 
turbidity  produced  in  the  100  c.  c.  of  baryta  water  by 
the  air  under  examination,  we  know  that  the  air  contains 
•05  vol.  of  carbonic  acid  per  cent.  If  2  c.  c,  or  more 
than  2,  are  required  to  imitate  the  turbidity  occasioned 
by  the  air,  the  air  is  bad  and  ventilation  is  defective. 

Dr.  Notter  advocates  the  trial  of  the  delicate  process 
of  Capt.  Abney,  which  is  described  in  the  Sanitary 
Record,  September  9,  1876  : — To  a  Florence  flask  of 
known  capacity  is  adapted  a  U-tube  half  filled  with 
coloured  spirit  and  to  which  is  fitted  a  scale  of  half  an 
inch.  A  small  glass  bulb  is  filled  with  a  saturated 
solution  of  caustic  potash  and  sealed  by  the  flame  of 
a  gas  jet.  The  bulb  is  broken  by  violently  shaking  the 
flask,  and  the  caustic  potash  set  free  combines  with  the 
carbonic  acid  contained  in  the  air  of  the  flask.  The 
production  of  a  partial  vacuum  depresses  the  spirit  in 
one  of  the  limbs  of  the  U-tube,  the  amount  of  which 
being  measured  furnishes  the  datum  from  which  a  cal- 
culation is  made  of  the  quantity  of  carbonic  acid  in  the 
flask. 

Simpler,  but   somewhat   less   accurate,  modes,  called 


CHEMICAL    EXAMINATION    OF    AIR 


the  household  and  minimetric  processes,  which  are 
sufficiently  exact  for  all  practical  purposes,  have  been 
proposed  by  Dr.  Angus  Sniith.^ 

The  outside  air  contains  an  amount  of  carbonic  acid,  H'^usehoid 
varying    between    "03    and    "06    per   cent,   but    is    most 
frequently  '04  per  cent,  which  rises  in  crowded  buildings 
and   other   close,  ill -ventilated   places  to  -25    per   cent. 


Method. 


Fig.  33. 


The  way  to  estimate  the  amount  roughly  is  to  wash 
different  measured  quantities  of  air  with  ^  oz.  of  lime 
water  in  such  bottles  as  are  here  depicted.  The  lime 
water  is  prepared  by  slaking  lime  with  water,  stirring 
the  slaked  lime  with  the  water,  and  then  allowing  the 
lime  to  subside.  The  clear  fluid  is,  after  1 2 ,  or  24 
hours,  poured  off,  and  is  ready  for  use.  A  table  has  been 
prepared  to  facilitate  the  use  of  this  plan  : — 


1  02).  cit. 


CHEMICAL    EXAMINATION    OF    AIR 


Size  or  Bottle. 
,    Ounces. 

Lime  Water. 
Point  of  observation  is 

no  jjrecipitate. 

Carbonic  Acid  in  air 

per  cent. 

20-6      .....          -03 

15-6 

•04 

12-5 

•05 

10-5 

•06 

9-1 

•07 

8-0 

•08 

7-2 

•09 

6-5 

•10 

6-0 

•11 

5-5 

•12 

5-1 

•13 

4-8 

•14 

4-5 

•15 

3-5 

•20 

2-9 

•25 

2-5 

•30 

2-0 

•40 

1-7 

•50 

1-5 

•60 

1-3      . 

•70 

1-2 

•80 

The  rule  to  remember  is  that  the  air  around  houses 
generally  contains  about  "04  per  cent  of  carbonic  acid, 
and  that  our  rooms  should  always  be  kept  so  that  a 
10-|-  oz.  bottle  full  of  air,  when  shaken  with  ^  oz.  of 
lime  water,  gives  no  precipitate.  We  then  know  that 
the  air  does  not  contain  more  than  '06  per  cent.  It 
is  often  difficult  to  keep  the  air  of  a  room  below  '07. 
If  a  precipitate  is  obserA^ed,  we  know  that  the  air 
does  contain  more  than  •06  per  cent,  and  we  take  a 
smaller  bottle,  say  a  9  oz.  bottle,  the  air  of  wdiich, 
when  shaken  with  ^  oz.  of  lime  water,  gives,  perhaps, 
no  precipitate.  We  then  say  the  air  is  worse  than  '06, 
and  not  worse  than  '07  ;  accordingly,  the  amount  must 
roughly  be  •07.  If  we  wish  to  test  the  air  as  expe- 
ditiously as  possible,  and  are  not  particular  to  ascertain 


CHEMICAL    EXAMINATION    OF    AIR  335 

the  exact  percentage,  we  may  take  a  bottle  of  a  size 
indicative  of  alternate  liundredtlis.  Instead  of  taking 
a  9  oz.  bottle  we  may  take  an  8  oz.,  and  treat  8  oz.  of 
air  in  the  same  manner.  If  we  obtain  no  precipitate 
we  know  that  the  air  is  not  worse  than  "08  per  cent. 
Having  already  ascertained  that  the  air  is  worse  than 
•06  we  conclude  that  the  air  is  contaminated  with  "07 
or  *08  per  cent  of  carbonic  acid. 

If  no  tnrbidity  is  occasioned  on  commencing  with 
our  10|-  oz.  bottle,  and  we  would  like  to  know  whether 
the  air  contains  as  much  as  "06  per  cent,  we  must  take 
a  larger  quantity  of  air,  for  example  a  12|-  oz.  bottle. 
If,  when  this  quantity  of  air  is  shaken  with  ^  oz.  of 
lime  water,  no  precipitate  is  procured,  we  know  that 
the  air  does  not  possess  more  than  '05  per  cent,  and  if 
a  precipitate  is  occasioned,  we  know  that  '06  per  cent 
is  the  amount. 

The  air  to  be  examined  is  best  introduced  into  the 
bottles  by  sucking  out  the  air  already  contained  in  them 
with  a  glass  tube.  Fresh  air  enters  to  supply  the  void 
we  create.  The  greatest  care  should  be  taken  not  to 
breathe  into  the  bottle,  for  our  breath  is  full  of  car- 
bonic acid.  The  bottles  should  be  wide -mouthed,  so 
that  the  sides  can  be  wiped  dry  and  clean.  If  the 
lime  cannot  be  readily  removed,  they  should  be  rinsed 
out  with  strong  hydrochloric  acid,  followed  by  an 
abundance  of  water.  There  is  great  difficulty  in  ob- 
taining bottles  of  exactly  the  capacity  required,  but 
this  could  be  overcome  if  there  was  any  demand  for 
such  measures,  by  the  special  manufacture  of  bottles 
to  hold  accurately  the  quantities  of  air  indicated. 

Ilimmetric  Method.  —  This  method  is  more  accurate,  ^i'"""^^"'° 

1     •  T     •  ^  r>i  n  -t  1-1  T       Method. 

and  involving  the  use  oi  but  lew  tools,  which  can  be 
conveniently  disposed  of  in  one's  pocket,  is  more  handy. 
It    consists  essentially    in    ascertaining   the    smallest   or 


336 


CHEMICAL    EXAMINATION    OF   AIR 


minimum  amount  of  air  required  to  produce  a  precipitate 
of  given  density — lience  tlie,  name.  Baryta  water,  which 
is  very  poisonous,  is  employed,  because  it  is  more  sen- 
sitive than  lime  water.  A  standard  precipitate  is  ob- 
tained by  shaking  -|-  ounce  of  baryta  water  in  a  23  oz. 
bottle  in  pure  air,  which  generally  contains  -04  per 
cent  of  carbonic  acid.  The  liquid  is  turbid  and  still 
translucent,  but  so  that  you  cannot  read  through  it. 
The  endeavour  is  to  ascertain  the  smallest  amount  of 
the  air  to  be  tested  which  is  necessary  to  produce  this 
standard  degree  of  turbidity.  We  take  a  bottle  which 
holds  exactly  2^  oz.,  and  place  in  it  ^  oz.  of  baryta 
water,  having  first  changed  the  air  in  the  bottle  by  a  few 
strokes  of  the  finger-pump ;  we  then  shake  the  2  oz.  of 
air  contained  in  the  bottle  with  the  ^  oz.  of  baryta  water, 
and  count  one  (vide  fig.  34). 


Fig.  34. 


We  then  pump  2  oz.  of  air  through  the  liquid  and 
again  shake  ^dolently  and  count  two.  When  the  tur- 
bidity is  such  that  the  words  written  on  the  slip  of  paper  ^ 
afl&xed  to  the  outside  of  the  bottle  become  indistinguish- 

1  The  words  written  witli  a  lead-pencil  on  the  label  must  be  of  such 
a  depth  of  shade  that  the  turbidity  of  the  standard  liquid  just  prevents 
them  from  beiue  seen. 


CHEMICAL    EXAMINATION    OF    AIR 


337 


able,  we  stop,  and  refer  to  a  table  that  lias  been  prepared 
to  economize  the  labour  of  calculation. 


Vol 

umes  of  Carbonic  Acid 

in  100  of  air. 

Number  of 

ballfuls              Wit 

h  2  oz. 

With  1  oz. 

of  air.                     1 

)aU. 

ball. 

1 

44 

2 

22 

3 

14 

4 

11 

5 

088 

6 

074 

7 

063 

8 

055 

9 

049 

10 

044 

17 

11 

040 

16 

12 

037 

14 

13 

034 

13 

14 

032 

12 

15 

029 

116 

16 

11 

17 

10 

18 

098 

19 

093 

20 

088 

21 

084 

22 

08 

23 

077 

24 

... 

•074 

The  J  oz.  ball  enables  us  to  estimate  greater  degrees  of  impurity  than  the  2  oz.  one. 

"When  the  air  of  a  place,  wMch  it  is  wished  to  test, 
feels  close  on  first  en- 
tering, I  use  the  2  oz. 
bottle,  and  if  very  close 
I  employ  the  ^  oz.  ball 
and  bottle. 

As  the  silk  valves 
are  rather  liable  to  get 
out  of  order,  I  dispense 
with  them,  and  simply 
make  a  slit  in  the  tube  ^'<5-  ^^- 


338 


CHEMICAL    EXAMINATION    OF    AIR 


Store 
Bottle. 


connecting  the  ball  and  bottle,  whicli  allows  of  the  expul- 
sion of  air,  but  prevents  its  ingress  {vide  fig.  35). 

A  weak  solution  of  baryta  ("1  to  "5  per  cent,  the 
exact  strength  being  unimportant)  is  employed,  which  is 
made  by  dissolving  caustic  baryta  in  distilled  water.  It 
must  be  stored  in  such  a  way  that,  on  removing  portions 
of  it,  air  undeprived  of  carbonic 
acid  shall  not  enter  the  store  bottle. 
The  arrangement  here  sketched, 
which  was  in  constant  use  in  the 
Board  of  Health  Laboratory,  Glas- 
^  gow,  and  is  to  be  found  in  Sutton's 
Volumetric  Analysis,  is  a  most  con- 
venient one  for  withdrawing  any 
quantities  that  are  required  of 
baryta  water,  or,  indeed,  of  other 
standard  solutions,  in  such  a  man- 
ner that  air  entering  is  freed  from 
whatever  body  the  contained  solu- 

A.  store  bottle  containing  soiu   tiou  is  designed  to  cxtract  from  it 

tion  of  caustic  baryta.  /^^^^  g       ggx 

B.  U  tube  fllled  witli  fragments    ^  . 

It  will  be  found  very  handy  to 
have  a  dozen  ^  oz.  stoj^pered 
bottles  with  wide  mouths,  and  to 
fill  them  from  this  store  bottle. 
It  is  needful  to  carry  a  stoppered 
and  capped  bottle  of  hydrochloric 
acid  to  clean  the  little  apparatus 
after  each  experiment,  before  it  is  washed  thoroughly 
with  water. 

In  the  air  of  a  room  which,  at  first  pure,  is  gradually 
vitiated  by  the  presence  of  persons,  the  smell  of  organic 
matter  begins  to  be  perceptible  to  one  entering  it  from 
the  fresh  air  when  the  carbonic  acid  reaches  '06  or  '07 
per  cent.     When  the  carbonic  acid  amounts  to  '09  or  '1 


Fig.  36. 


of  pumice  stone  moistened 
with  caustic  potash,  through 
which  air  passes  in  order  to 
enter  the  store  bottle. 

C.  Burette  graduated  in  any 
manner  that  is  required. 

D  D.  Shelves. 

E  E  E.  Black  indiarubber  tubes. 

P.  Clip. 

G.  Rod  for  support  of  burette. 


CHEMICAL    EXAMIXATION    OF    AIR  3  3 'J 

per  cent,  the  air  is  termed  "  close  "  or  "  stuffy."  The 
fcetid  odour  of  organic  matter  becomes  very  disagreeahle 
when  the  carbonic  acid  exceeds  "1  per  cent. 

When  the  carbonic  acid  is  as  much  as  from  '15  to  '3 
per  cent,  headache  and  vertigo  are  experienced,  as  the 
result  of  the  vitiation  of  the  air  by  this  gas  and  its 
accompanying  impurities. 

When  people  speak  of  good  ventilation,  they  mean 
air  with  less  than  *07  per  cent. 

A  rough-and-ready  mode  of  detecting  the  presence  of  Detection  „f 
hydrogen  sulphide  in  the  air,  wliich  is  a  gas  produced  in  suiphkie, 
the    decay   of   organic    matter — for    example,    in    some  ainmoDium 

/  ®  .  -■-      '  sulphide, 

marshes,  in  sewer  gas,  etc. — is  bv  means  of  acetate  of  lead  and 
papers.  "  ''"™""'^- 

Ammonium  sulphide,  which,  with  hydrogen  sulphide, 
is  a  constituent  of  sewer  gas,  is  detected  by  nitro-prusside 
of  sodium  tests.  Ammonia,  a  product  of  putrefaction 
and  decomposition,  is,  if  in  large  amount,  observed  by 
means  of  logwood  papers. 


CHAPTEE    XXVIII 

THE    BIOLOGICAL   EXAMINATION    OF    AIR 

The  examination  of  air  biologically  resembles  closely  that 
of  water.  The  difference  consists  in  the  arrangements 
Collectors  for  Collecting  from  the  air  the  micro-organisms  or  germs 
organisms  containccl  in  it.  A  glass  jar  about  6  inches  high  plugged 
with  a  stopper  of  cotton  wool,  containing  at  its  bottom  a 
shallow  glass  capsule,  which  can  be  easily  removed  by 
the  help  of  a  brass  lifter  and  charged  with  sterile  jelly,  is 
opened  to  the  access  of  the  air  under  examination  for  a 
certain  number  of  seconds  or  minutes.  Cohn  and  Miflet 
employ  Wolff's  bottles  (in  which  the  sterile  jelly  is 
placed)  and  an  aspirator  or  a  Sprengel  pump  to  draw  a 
definite  amount  of  air  through  the  same.  Hesse  sub- 
stitutes a  long  horizontal  fixed-glass  cylinder  for  the 
Wolff's  bottles,  along  the  floor  of  which  the  liquefied 
nutrient  jelly  is  allowed  to  solidify.  Dr.  Maddox's  com- 
bined aeroscope  and  aspirator  has  been  employed  as  a 
collector  {vide  page  298).  A  shallow  watch  glass  filled 
with  a  nutrient  jelly  may  be  placed  on  the  glass  plate 
in  the  bell  jar  receiver  depicted  in  Fig.  21  (page  300),  in 
the  mouth  of  which  is  an  indiarubber  cork  perforated 
with  two  holes  for  entrance  and  exit  glass  tubes,  the 
latter  being  connected  with  a  Dancer's  aspirator,  by  the 
help  of  which  a  known  number  of  cubic  inches  of  air  can 
be  transmitted  over  the  sterile  jelly.  For  the  composition 
and  mode  of  preparation  of   Koch's  nutrient  jeUy  vide 


BIOLOGICAL    EXAMINATION    OF    AIR 


341 


page  75.  The  nutrient  jelly  in  whatever  manner  it  is 
inoculated  is  placed  in  the  "  damp  chamber  "  {vide  fig.  9, 
page  83),  or  is  maintained  in  the  incubator  at  a  tempe- 
rature of  from  68°  F.  to  77°  F.,  and  daily  inspected. 
The  number  of  colonies  or  foci  of  growth  which  appear  on 
the  jelly  can  be  counted  or  calculated  approximatively  as 
described  on  page  84.  After  the  trial  of  many  different 
kinds  of  collectors,  the  form  of  apparatus  at  length 
adopted  by  M.  Pierre  Miquel  at  the  Montsouris  Observa- 
tory and  its  mode  of  employment  is  thus  described.^ 
It  consists  of  a  glass  flask 
with  a  long  neck,  which  ex- 
tends downwards  into  its  in- 
terior and  terminates  in  a 
minute  aperture.  The  mouth 
of  the  flask  is  protected  by 
a  hood  A  furnished  with  a 
plug  of  sterilized  cotton  wool 
{vide  fig.  37).  The  flask 
possesses  two  lateral  tubes ; 
the  one  marked  C  being  pro- 
vided with  two  plugs  of 
cotton  wool,  and  the  other 
B  being  attached  by  a  piece  of  rubber  tube  to  a  sealed 
up  point  of  glass  tube. 

Preparation  for  Experiment. — From  30  to  40  c.  c.  of 
distilled  water  are  introduced  into  the  flask,  which  is  then 
heated  for  two  hours  at  230°  F.  in  a  steam  bath.  After 
cooling  it  is  placed  in  the  incubator  ready  for  use.  2  0  or 
3  0  little  glass  flasks,  each  containing  beef  broth,  are  then 
sterilized,  so  as  to  be  fit  for  inoculation. 

Experiment. — A  caoutchouc  tube  is  fitted  to  C  and 
an    aspirator    (after    the    removal    of    the    hood)    being 
attached,  a  certain  known  amount  of  air  is  drawn  through 
^  Annuaire  de  V  Ohservatoire  de  Montsouris  for  1886. 


Fig. 


342  BIOLOGICAL    EXAMINATION    OF    AIR 

the  fluid.  The  hood  having  been  strongly  heated  during 
its  time  of  withdrawal  is  replaced. 

End  of  Experiment. — By  alternate  pressure  and 
removal  of  pressure  on  the  caoutchouc  tube  attached  to 
0,  the  liquid  is  raised  up  and  down  the  tubular  neck  10 
or  12  times  in  order  to  wash  its  interior.  After  having 
broken  oft'  the  sealed  point  B,  we  distribute  the  liquid  in 
fractional  proportions  amongst  the  glass  flasks  containing 
sterilized  beef  broth.  Finally  25  c.  c.  of  this  broth  are 
introduced  into  the  glass  collector  itself,  and  the  internal 
plug  of  cotton  wool  in  the  tube  C  is  projected  into  the 
flask  by  means  of  a  platinum  wire  which  has  been  heated. 
The  amount  of  air  passed  by  the  aspirator  should  have 
been  pre\'iously  determined  and  proportioned,  so  that  ^th 
or  l^ths  of  the  inoculated  broths  shall  remain  perfectly 
limpid.  In  this  manner  we  are  enabled  to  operate  on  a 
mixture  of  micro-organisms  and  water  sufficiently  dilute 
to  admit  of  a  calculation  of  their  number. 

M.  Miquel,  by  means  of  an  aspirator  attached  to  a 
clockwork  apparatus,  on  wliich  is  exposed  a  nutritive 
paper  ^  covered  with  a  thick  layer  of  freshly  sterilized 
gelatine,  also  registers  hourly  the  quantity  of  bacteria  and 
germs  contained  in  air  by  the  enumeration  of  the  number 
of  colonies  subsequently  developed  on  it.  He  gives  the 
accompanying  records  thus  taken  of  pure  and  impure  air. 

1  Mode   of   preparation   described   in   Annuccire   de    V Ohservatoire  de 
3Iontsoicris  for  1886. 


r 


\^^ 


pure  aif . 


impm'e  air 


9k 


lo  &ee  page  34-1 


CHAPTEE    XXIX 

METALLIC    POISONS  : AESENIC,    COPPER,    AND    LEAD 

Arsenic,  copper,  and  lead  are  sometimes  found  in  the  air  in^genic, 
the  neioiibourhood  of  smeltino;  works,  etc.     The  determina-  copper,  ar.ci 

lead. 

tion  of  the  amount  of  these  metals,  which,  when  diffused 
through  the  air,  exercise  injurious  effects  on  animal  and 
vegetable  life,  fall  rather  within  the  scope  of  those  legis- 
lative enactments  that  concern  the  contamination  of  the 
air  by  manufactories,  such  as  the  Alkali  and  Works 
Eegulation  Act  of  1881,  under  which  scientific  chemists 
are  appointed  as  inspectors.  The  human  system  itself, 
when  continually  exposed  to  the  poisonous  influences  of 
copper  and  lead,  affords  an  excellent  test  of  an  exposure 
to  an  injurious  amount  in  the  case  of  those  who  work 
with  these  metals,  such  for  instance  as  miners  in  copper 
mines,  or  painters.  The  effects  on  the  body  of  these 
metals,  even  in  the  smallest  doses,  are  so  well  known  to 
every  physician,  that  he  requires  but  little  chemical  aid. 

It  is  different  in  the  case  of  arsenic,  for  the  effects  of 
this  metal  give  rise  in  minute  doses  to  such  obscure  and 
incomprehensible  symptoms  of  such  great  variety,  that 
they  often  cannot  be  assigned  to  their  rightful .  cause 
without  chemical  assistance. 

A  description  of  the  several  poisonous  colours  used  to 
tint  the  cheeks,  the  hair,  etc.,  to  avert  the  appearance  of 
old  age  and  to  dye  articles  of  wearing  apparel,  will  not 
fall  within  the  province  of  this  work,  because  they  exert 


344  METALLIC    POISONS 

their  poisonous  effects  by  coming  into  contact  with  the 
skin.     Arsenic,  mercury,  lead  in  the  form  of  magenta, 
coraline,^  and  other  of  the  new  dyes,  are  some  of  the 
most  common  poisons  thus  used  {vide  page  261). 
rsenicai  Instances  of  the  terrible  suffering,  misery,  and  even 

rail  paper.  ^^^^^^  |-|-^g^l-  y^^lYQ  occurrcd  from  the  use  of  arsenical  wall 
papers,  from  the  preparation  for  sale  of  feathers,  artijScial 
flowers,  leaves,  fruit,  etc.,  swarm  in  medical  publications. 
The  poisonous  greens,  such  as  Scheele's,  Schweinfurth's, 
Brunswick,  Emerald,  Paris,  wliich  are  all  confounded 
together  by  work-people,  are  used  in  enormous  quantities, 
partly  because  they  are  very  attractive  in  appearance  and 
partly  because  they  are  cheap.  Not  less  than  700  tons 
of  these  deadly  greens  are  consumed  in  trade  annually  in 
this  country.  Many  wall  papers  that  are  not  green  are 
loaded  with  arsenic,  especially  pale  or  white  drawing- 
room  papers,  with  an  enamelled  or  opal  white  ground, 
which  have  yielded  15  to  25  grains  of  arsenic  per  square 
foot.  The  late  Mr.  Wigner,  on  examining  samples  some 
years  ago  of  all  the  papers  in  a  ten-roomed  house,  none  of 
which  were  gTeen,  discovered  that  five  of  them  contained 
arsenic  in  such  quantity  as  to  be  injurious  to  health. 

The  Medical  Officer  of  Health,  in  his  inquiries  after  the 
causes  of  vague  and  obscure  forms  of  illness,  may  often 
have  occasion  to  examine  the  air  of  rooms  poisoned  by 
arsenic  papers  and  furnishing  materials.  The  public  will 
not  unfrequently  bring  him  portions  of  wall  paper  w^ith 
which  their  rooms  are  adorned,  in  order  that  he  may 
examine  them  and  express  an  opinion  thereon.  It  is  as 
weU,  therefore,  for  him  to  be  acquainted  with  a  simple 
means  of  testing  for  arsenic,  not  only  to  aid  him  in  his 
own  investigations,  but  to  assist  the  public  and  their 
medical  attendants.     If  it  is  wished  to  ascertain  whether 

^  Bulletin  de  I'Academie  InqKriale  de  Medicine,  February  and  Marcli 
1869. 


METALLIC    POISONS 


345 


a  paper  does  or  does  not  contain  arsenic,  the  paper  is 
scraped  with  a  penknife,  and  the  dust  that  is  removed 
is  tested.  If  we  desire  to  find  out  whether  particles  of 
dust  have  detached  themselves  from  the  paper,  and 
poisoned  the  air  of  the  room,  the  dust  that  lies  on  the 
articles  of  furniture  may  be  collected  for  examination. 
The  dust  of  the  paper,  in  whatever  way  oljtained,  is 
mixed  with  an  equal  bulk  of  bicarbonate  of  soda  (dried 
over  a  spirit  lamp)  and  a  little  powdered  charcoal.  The 
mixture  is  placed  in  a 
dry  test  tube  and  heated. 
If  arsenic  is  present,  the 
characteristic  odour  of 
garlic  is  perceived,  and 
a  mirror  of  metallic 
arsenic  is  obtained  as  a 
ring  on  the  sides  of  the 
tube.  If  the  test  tube 
is  large,  so  as  to  allow 

of  free  access  of  air,  octahedral  crystals  of  arsenious  acid, 
easily  recognized  by  the  microscope,  will  be  found  in- 
stead of  the  mirror.  Eeinsch's  test  may  be  employed 
to  show  the  presence  of  arsenite 
of  copper  in  a  paper.  The  paper 
having  been  soaked  in  a  solu- 
tion of  ammonia,  which  will  dis- 
solve the  arsenite  of  copper  form- 
ing a  blue  liquid,  is  acidified 
with  hydrochloric  acid  and  then 
boiled  in  a  test  tube  with  one  or 
two  strips  of  brilliant  untarnished-^ 
copper.       If   arsenic    be    present  ^'^"  "^' 

the  polished  metal  acquires  a  steel-gray  coating. 


The 


^  Cojiper  may  be  cleaned  by  heatiug  it  in  a  flame,  by  then  applying  a 
little  nitric  acid  to  it,  and  lastly  ^vasbing  it  in  water. 


!46 


METALLIC    POISONS 


copper  is  washed,  dried  on  filter  paper,  and  heated 
in  a  small  test  tube  over  a  Bunsen's  burner  or  spirit 
lamp,  when  arsenious  acid  in  octahedral  crystals,  readily 
diagnosed  by  the  microscope  (vicle  fig.  39),  will  be 
deposited  in  the  cool  part  of  the  tube,  if  the  paper  con- 
tains arsenic. 

Or  the   green   colouring  matter  may  be   scraped   off 
the  paper  and  dissolved  in  pure  hydrochloric  acid  and 

water,  and  examined  by 


Marsh's  test.  Granula- 
ted zinc,  or  zinc  foil  in 
fragments,  is  introduced 
into  a  flask  with  some 
water,  and  a  little  pure 
sulphuric  acid  is  poured 
down  the  funnel.  A 
few  minutes  should  be 
allowed  to  elapse  for 
the  removal  of  all  the 
^  air  from  the  flask.  The 
gas  evolved  should  then 


Fig.  40. — Maksh's  Test. 
A.  Flask  containing  dilute  sulphuric  acid  and 


be    collected    in   a   test 
tube,  and  a  lighted  match 

zinc  free  from  all  traces  of  arsenic.  '^6     appiiecl     tO    the     tCSt 

B.  Test  tube  for  collecting  small  quantities  of  tube  tO  aSCCrtaiu  whether 
the  gas  evolved. 

C.  Tube  of  hard  Bohemian  glass  that  will  not   a    miXturC    of     hydrOgCU 
fuse,  drawn  out  to  a  point  so  as  to  form  a  jet.        ^^^     atmOSphcric     air    is 

escaping,  or  whether  hydrogen  is  alone  given  off.  If  air 
is  still  bemg  expelled  from  the  apparatus  the  gas  in  the 
test  tube  on  being  lighted  will  explode  harmlessly.  The 
gas  escaping  at  the  jet  should  on  no  account  be  ignited 
until  two  or  three  of  these  trials  have  been  made. 
When  the  gas  collected  in  the  test  tube  does  not  explode, 
it  is  safe  to  light  the  jet.  Having  ascertained  the  purity 
of   the   chemicals   employed,   by   depressing   a   piece   of 


METALLIC    POISONS  347 

porcelain  on  the  flame,  the  solution  of  the  green  colour- 
ing matter  may  be  passed  down  the  tube  funnel  and  the 
flame  again  tested.  If  it  consists  of  arsenic  there  will 
be  a  dark  mirror  of  arsenic  deposited  on  the  porcelain. 

If  there  is  any  doubt  as  to  the  purity  of  the  chemicals. 
Dr.  E.  Davy's  sodium  amalgam  test,  which  finds  so  much 
favour  in  the  United  States,  may  be  substituted,  since 
sodium  and  mercury,  of  which  the  sodium  amalgam  is 
formed,  are  generally  free  from  arsenic.  This  amalgam  Dr.  Davy's 
is  prepared  by  adding  1  part  of  sodium  to  8  or  10  of^^^J™^ 
mercury,  and  supplies  us  with  a  ready  means  of  obtaining  test, 
hydrogen  free  from  arsenic.  It  evolves  hydrogen  gas 
when  water  is  added  to  it.  A  fragment  of  sodium 
amalgam  is  dropped  into  a  flask  and  the  solution  sup- 
posed to  contain  arsenic  is  introduced.  A  strip  of  paper 
moistened  with  an  acidified  solution  of  nitrate  of  silver 
("25  gramme  arg.  nit.,  5  grammes  of  water,  and  2  drops 
of  nitric  acid)  is  blackened  if  held  at  the  mouth  of  the 
flask.  To  verify  the  result,  it  is  as  well  to  treat  the 
blackened  paper  with  ammonium  sulphide.  The  sulphide 
formed  is  insoluble  in  hydrochloric  acid  if  arsenic  be 
present,  and  is  soluble  in  hydrochloric  acid  if  antimony 
be  present. 

If  it  is  wished  to  ascertain  the  amount  of  arsenious 
acid  (the  common  white  arsenic  of  commerce)  contained 
in  a  paper,  a  rough  estimate  may  be  easily  formed.  If 
the  pattern  of  the  paper  consists  of  groups  of  green  leaves, 
as  is  often  the  case,  scrape  off  all  the  green  arsenite  from 
a  single  leaf  and  weigh  it.  The  number  of  leaves  in  each 
square  foot  of  surface  of  the  paper  having  been  counted, 
and  the  dimensions  of  the  room  having  been  taken,  the 
number  of  leaves  in  the  room  is  easily  ascertained.  If 
the  green  colouring  matter  is  equally  distributed  over  the 
surface  of  the  paper  a  square  inch  of  the  paper  should  be 
operated  on  in  place  of  a  single  leaf.     A  measurement  of 


34:8  METALLIC    POISONS 

the  room  will  readily  give  the  number  of  square  inches 
of  surface.  Two  or  three  green  leaves  of  a  wall  paper 
were  recently  sent  to  me  with  the  request  that  I  would 
ascertain  whether  the  green  pigment  contained  arsenic, 
and,  if  so,  the  quantity  of  the  same.  It  had  been 
estimated  by  the  applicant  that  there  were  about  22,800 
leaves  in  the  room. 

All  the  green  colour  having  been  scraped  off  from  a 
single  leaf,  by  the  help  of  a  penknife,  was  found  to  weigh 
16  milligTammes. 

Arsenite  of  Copper.  Arsenious  Acid. 

2  Cu.  0.,  H  0.,  Asg  O3 


375  :    16 


118S 
198 


Arsenious  Acid. 


375\3168/8 
/3000V 


To  convert  the  8  milligrammes  of  arsenious  acid  into 
fractions  of  a  grain,  a  weight  that  is  more  readily  under- 
stood by  the  public,  it  is  simply  necessary  to  multiply  by 
15-5  and  divide  by  1000. 

Milligram.  Milligram.  Grs.  in  1  gramme. 

1000  :     8  :     :     15-5 


1000)124-0(-124 

Ans.  One  leaf  contains  '124  of  a  grain,  which  is 
equivalent  to  124  grains  of  white  arsenic  in  every 
1000  leaves,  or  nearly  6  ounces  in  the  room. 

Some  wall  papers  contain  compounds  of  lead  and 
copper  (non- arsenical),  but,  although  their  employment 
is  undesirable,  we  have  but  little  evidence  at  present 
which  would  forbid  their  use. 


INDIRECT  METHOD 
CHAPTEE   XXX 

ESTIMATION    OF    OZONE    AND    OTHER   AIR   PURIFIERS 

The  whole  subject  is  so  vast  that  it  is  extremely  difficult 
to  know  how  to  concentrate  it  without  omitting  salient 
points  of  great  interest. 

Ozone. — Ozone  is  condensed  oxygen,  or  a  very  active,  ozone 
lively,  and  energetic  form  of  this  life-giving  gas.  Its 
object  in  nature  is  to  destroy,  or,  to  speak  more  correctly, 
to  render  harmless  by  oxidation  all  offensive  noxious 
products  that,  if  permitted  to  accumulate,  would  produce 
disease  and  extinguish  life. 

Take,  for  example,  a  little  blood,  and  keep  it  in  a 
warm  place  for  months,  until  it  putrefies.  Wlien  the 
odour  is  something  horrible,  sufficient  indeed  to  create 
nausea,  or  sickness,  send  a  stream  of  ozone  over  it,  and 
its  freshness,  purity,  and  sweetness  will  be  restored. 
Neither  ozone  nor  the  other  air  purifiers  are  to  be  found 
in  the  air  of  unventilated  inhabited  rooms  or  hospitals 
unless  the  windows  are  open,  being  speedily  used  up,  and 
not  replaced  as  they  should  be  by  the  admission  of  fresh 
air,  which  nearly  always  contains  them  in  greater  or  less 
quantity. 

Ozone  can  be  prepared  in  a  great  variety  of  ways. 
It  is  perhaps  most  conveniently  made  by  mixing  three 
parts  of  sulphuric  acid  with  two  parts  of  permanganate 


350  OZONOMETKY 

of  potash.^  This  mixture  will  continue  to  give  off  ozone 
for  several  months.  It  is  associated  in  the  air  with 
other  purifying  agents,  such  as  peroxide  of  hydrogen 
and  acids  of  nitrogen.  Peroxide  of  hydrogen,  called  also 
oxygenated  water,  is  produced  by  a  combination  of  the 
oxygen  of  the  air  with  water.  It  is  found  sometimes  in 
rain  and  snow.  It  also  is  a  powerful  oxidizing  agent,  for 
it  very  freely  parts  with  its  excess  of  oxygen.  Its  oxidiz- 
ing powers  render  it  useful  for  bleaching,  as  it  attacks 
vegetable  colours  vigorously.  Young  ladies  used  to 
purchase  it  for  bleaching  their  hair,  under  the  name  of 
"  auricomus,"  when  it  was  the  fashion  for  every  one  to 
exhibit  flaxen  locks.  It  so  readily  parts  with  its  oxygen 
that  a  temperature  of  68°  E.  is  sufficient  to  disengage  it, 
the  warmth  of  the  hand  to  the  bottle  which  holds  it 
being  often  dangerous  when  it  is  quite  pure.  Nitrous 
acid  is  produced  whenever  an  electric  spark  passes 
through  the  air.  It  is  one  of  the  most  valuable  gaseous 
disinfectants  and  deodorizers  known.  It  acts  most 
energetically  on  organic  impurities,  removing  the  un- 
pleasant odours  of  the  dead-house  more  readily  (so  it  is 
said)  than  any  other  gas.  This  rapid  action  arises  from 
the  facility  with  which  it  gives  up  its  oxygen.  For 
deodorizing  purposes,  it  is  made  by  mixiag  nitric  acid 
and  water  with  copper  turnings.  It  is  used  more  on  the 
Continent  than  in  this  country.  The  amount  of  ozone, 
peroxide  of  hydrogen,  and   nitrous   acid,  which  are   all 

^  Dr.  Leeds  states  that  wheu  permanganate  of  potash  is  exposed  to  the 
action  of  sulphuric  acid,  chlorine  is  evolved  in  consequence  of  the  presence 
of  an  impurity  in  the  shape  of  a  chlorate.  Apart  from  the  ease  ^vith  which 
chemistry  enables  us  to  distinguish  ozone  from  chlorine,  the  smell  of  these 
two  bodies  is  so  difierent  that  there  can  be  no  difficulty  in  diagnosing  the 
one  from  the  other.  Moreover  on  the  fact  that  permanganate  of  potash 
emits  oxygen  when  under  the  influence  of  sulphuric  acid,  rests  the  ex- 
cellent process  for  the  estimation  of  peroxide  of  hydrogen  in  which  the 
oxygen  produced  is  measured. 


OZONOMETRY  351 

powerful  air  purifiers,  are  measured  by  exposing  to  the 
air  paper  dipped  in  a  solution  of  iodide  of  potassium. 
They  all  have  the  property  of  breaking  up  this  salt  and 
setting  free  the  iodine,  which  gives  the  paper  a  reddish 
brown  colour,  of  greater  or  less  depth,  according  to  the 
amount  of  these  disinfectants  present  in  the  air  during 
the  time  of  its  exposure.  Sometimes,  instead  of  all  the 
iodine  being  set  free,  some  of  it  goes  to  form  an  oxide  of 
potassium,  called  the  iodate  which  is  a  colourless  salt. 
It  is  therefore  always  necessary  to  spray  these  tests  after 
exposure  with  a  solution  of  tartaric  acid  which  sets  free 
the  iodine  from  the  iodate,  but  does  not  interfere  with 
the  unacted  upon  iodide  of  potassium.  We  are  then  sure 
of  obtaining  all  of  the  iodine  set  at  liberty  by  the  air 
purifiers.  If  we  wish  to  ascertain  the  amount  of  ozone 
present  in  the  air  to  the  exclusion  of  the  other  air 
purifiers,  we  employ  a  paper  which  is  alone  acted  upon 
by  ozone,  such  as  the  iodized  litmus  paper.  "With  this 
test  we  do  not  take  any  notice  of  the  amount  of  iodine 
set  free,  but  we  observe  the  amount  of  potash  formed  by 
the  union  of  the  ozone  with  the  potassium.  Potash, 
being  an  alkali,  of  course  has  the  property  of  turning  red 
litmus  blue,  whilst  an  acid  turns  blue  litmus  of  a  red 
colour.  The  greater  or  less  conversion  of  the  red  litmus 
into  blue,  shows  a  greater  or  less  quantity  of  ozone  in 
the  air. 

Scales  have  been  prepared  for  estimating  the  depth 
of  colour  of  the  iodine  papers  in  testing  the  amount  of 
the  three  air  purifiers,  and  of  the  iodized  litmus  papers 
for  showing  the  amount  of  ozone. 

It  was  formerly  the  practice  to  employ  starch  tests,  iodized 
which  are  composed  of  a  mixture  of  iodide  of  potassium  ^g^f^ 
and  boiled  starch,  which  became  blue  on  exposure  to  the 
air  from  the  formation  of  the  blue  iodide  of  starch.     There 
are  many  different  kinds,  which  may  be  looked  upon  now 


352  OZONOMETEY 

as  curiosities ;  for  example,  Schonbein's,  Lowe's,  Jame  de 
Sedan's,  Lender's,  Moffat's,  etc.  They  are  all  more  or 
less  disposed  to  behave  in  an  eccentric  fashion ;  now  they 
colour,  then  they  bleach ;  sometimes  they  tint  in  a  uni- 
form manner ;  at  other  times  they  become  marked  with 
lines  like  a  Scotch  plaid,  or  with  spots  ;  whilst  they  very 
frequently  fade.  Hence  the  records  of  observations  ap- 
pear most  contradictory,  forming  a  mass  of  almost  inex- 
tricable confusion.  In  support  of  this  assertion,  the 
opinions  of  a  few  who  have  made  ozone  a  subject  of  study 
may  be  quoted  : — 

"  At  the  present  time  the  modes  of  determining  ozone, 
and  the  tests  for  ozone  in  the  external  air  are  very  unsat- 
isfactory."— Dr.  Richardson. 

"  The  greater  part  of  the  countless  observations  on 
the  amount  of  ozone  in  the  air  are  worthless." — Frof. 
Heaton. 

"  The  determinations  which  have  hitherto  been  made 
are  very  vague  and  unsatisfactory." — Dr.  Wetlurill. 

"  Tests  prepared  from  the  same  recipe,  by  different 
persons,  give  varied  results." — Boehm. 

"If  we  expose  the  tests  of  Schonbein  and  Moffat 
together  we  do  not  get  the  same  result,  and  even  tests 
made  by  the  same  persons  at  two  different  times  will  not 
read  alike." — Mr.  Loive,  of  Nottingham. 

"  All  the  methods  employed  are  more  or  less  defec- 
tive."— Dr.  Scoresby-Jackson. 

"  Until  more  certain  means  are  discovered  for  estima- 
ting ozone,  present  observations  must  be  received  with 
great  caution." — Davies. 

"  The  estimation  of  ozone  is  in  a  very  unsatisfactory 
state.  The  great  imperfection  in  the  tests  make  it  desir- 
able to  avoid  all  conclusions  at  present." — Prof.  ParJces. 

"No  clear  and  consistent  results  have  yet  been 
obtained.     Variations  of  light,  wind,  time,  and  paper,  may 


OZOXOMETliY  ooo 

cause  clianges  attribiited  only  to  ozone,  and  there  are  no 
reliable  means  of  checking  them." — Admiral  Fitzroy. 

"  jSTo  trustworthy  observations  on  ozone  are  made  in 
the  United  States  of  America." — Dr.  Henry  of  the  Smith- 
fiOJiian  Institiition. 

These  views  refer  to  the  antiquated  practice  of  esti- 
mating atmospheric  ozone  with  the  iodized  starch  test,  by 
suspension  in  a  cage  or  box,  and  subsequent  comparison 
with  a  scale  containing  gradations  of  colour. 

The  exposure  of  any  kind  of  test  papers  in  cages  is  a 
most  fallacious  mode  of  observation,  for  they  are  measurers 
of  the  velocity  of  the  wind,  and  may  be  called  anemo- 
meters rather  than  ozonometers.  The  higher  the  wind 
the  deeper  the  colours  they  assume,  for  the  simple  reason 
that  more  air  passes  over  them. 

There  is  a  special  fallacy  attendant  on  the  employ- 
ment of  starch  tests  in  ozonometry,  because  there  is  every 
reason  to  believe  that  the  iodide  of  starch  is  not  a  true 
chemical  compound.  ]\I.  Duclaux  declares  that  its  forma- 
tion is  purely  physical,  and  results  from  the  adhesion  of 
the  molecules  of  its  constituents.  It  appears  that  JM. 
Personne  and  M.  Guichard  expressed  the  same  opinion 
some  years  ago.  The  latter  chemist,  who  examined  the 
iodide  of  starch  by  the  aid  of  the  dialyser,  writes — "  The 
so-called  iodide  of  starch  is  simply  starch  tinted  with 
iodine."  Watts  considers  that  "the  blue  coloration  is  due 
to  the  formation  of  a  loose  combination  of  starch  and 
iodine,  or  perhaps  to  the  mere  mechanical  precipitation 
of  the  iodine  upon  the  starch."  The  various  circumstances 
which  affect  and  modify  the  colour  of  the  iodide  of  starch 
have  been  pointed  out  by  Gmelin.^ 

Then,  again,  all  of  the  iodine  set  free  in  tlie  starch 
test  does  not  sometimes  combine  with  the  starch.  Some 
of  the  iodine  set  free  occasionally  forms  a  colourless  iodate. 

1  Handbook  of  Chemistry,  xv.  97  (German  edition). 
2  A 


354  OZONOMETRY 

It  is,  moreover,  very  difficult  to  obtain  pure  starch,  and 
samples  of  the  same  kind  of  starch  often  vary  much  in 
strength.  The  errors  associated  with  the  employment  of 
iodide  of  starch  tests  are  indeed  legion. 

Notwithstanding  the  existence  of  these  irremediable 
defects  inherent  to  the  employment  of  iodide  of  starch  in 
atmospheric  ozonometry,  which  were  brought  by  me  before 
the  scientific  world  in  a  prominent  manner  in  1873, 
the  officials  at  the  Montsouris  Observatory  have  been 
throwing  away  their  time  and  labour  by  employing 
cotton  wool  impregnated  with  iodide  of  potassium  and 
starch.  They  have  at  length,  it  seems,  discovered  that 
what  I  told  them  years  ago  is  but  too  true — namely, 
that  the  iodide  of  starch  test  is  wholly  unreliable.  M. 
Marie-Davy  writes  : — "  La  difficulte  de  la  methode  con- 
siste  en  ce  que  I'iodure  d'amidon  manque  de  stabilite, 
qu'il  se  decolore  a  I'air,  et  qu'en  presence  de  la  potasse 
formee  une  partie  de  I'iode  mis  en  liberte  peut  se  trans- 
former en  iodate.  D'un  autre  cote,  I'amidon  s'altere  au 
contact  de  I'air  et  des  produits  pyrogenes  qu'on  rencontre 
toujours  dans  I'atmosphere  des  grandes  villes."  They 
have  now  forsaken  this  untrustworthy  iodide  of  starch 
reaction,  and  estimate  the  quantity  of  oxygen  employed 
in  the  conversion  of  an  arsenite  into  an  arsenate,^  and 
efforts  have  been  made  to  bolster  up  the  belief  in  the 
starch  tests  of  Schonbein,  by  making  it  appear  that 
Schonbein's  starch  tests — plus  certain  corrections — agree 
in  their  indications  with  the  results  determined  by  the 
oxidation  of  an  arsenite.      Having  had  such  an  immense 

^  The  average  amount  of  ozone  furnished  by  this  process  for  the  eight 
years  1877-1884  shows  a  remarkable  constancy  in  the  composition  of  the 
air. 

Ozone  in  100  cubic  metres  of  air  in  the  Park  of  Montsouris,  near  Paris. 
Milligrammes. 
1877       1878       1879       1880       1881       1882       1883       1884 
1-9         1-5  -8  -6  1-  -7  11         1-7 


OZONOMETKY  355 

experience  with  starch  tests,  my  intimate  acquaintance 
with  their  comic  behaviour  would  incline  me  to  think 
that  if  there  is  any  harmony  between  them  and  the  pro- 
cess with  the  compound  of  arsenic,  the  latter  must  be 
worthless  also. 

According  to  the  most  approved  recent  mode  of 
observing  ozone,  and  of  estimating  the  amount  of  the  air 
purifiers  (ozone,  peroxide  of  hydrogen,  and  nitrous  acid), 
it  is  necessary  to  pass  a  known  quantity  of  air  over  test 
papers  of  two  different  kinds  at  a  knoion  and  unvarying 
velocity  by  means  of  aspirators,  of  which  there  is  a  great 
variety,  such  as  Mitchell's  aspirator,  the  tube  aspirator, 
Dancer's  aspii^ator,  the  injection  aspirator,  Andrews'  as- 
pirator, the  Montsouris  aspirator,  and  the  clockwork  fan 
aspirator.  The  test  papers  are  exposed  in  a  box  of  a 
peculiar  form,  where  they  are  protected  from  dust,  light, 
and  moisture. 

It  would  be  impossible  to  give  the  reader  in  this 
handbook  an  adequate  description  of  the  mode  in  which 
ozone  and  the  other  air  purifiers  should  be  estimated. 
The  fullest  information  as  to  how  these  bodies  should  be 
observed  has  already  been  published  by  me  in  my  work 
on  Ozone  and  Antozone,  in  which  it  occupies  136  pages. 
The  errors  associated  with  the  old  ozonometric  method  of  Errors  con- 

,         T      .       .  T       ,  .       -,  nected  with 

exposing  starch  tests  may  be  here  summarized.  ow  method. 

1.  Impurity    of    chemicals  )  employed  in  the  manufac- 

2.  „  „     paper         j       ture  of  the  tests. 

3.  Formation  of  the  iodate  of  potash. 

4.  Non-union  with  the  starch  of  the  whole  of  the  liberated 

iodine. 

5.  Changes  in  the  force  of  the  wind. 

6.  Bleaching  and  fading  of  coloured  tests  from — 

A.  Formation  of  the  iodate  of  potash. 

B.  Excess  of  moisture  in  the  air. 

C.  A  high  temperature  of     „ 


356  OZOXOMETRY 

D.  A  great  velocity  of  tlie  air. 

E.  A  long  exposure  to       „ 

F.  Sulphurous  acid  in       „ 

7.  Light. 

8.  Ozonometers  (  =  chromatic  scales)  faulty  in  construction. 

9.  Differences  of  aspect  and  ele-s-ation. 

I  must  refer  to  that  work  for  the  blue  and  red  chro- 
matic scales,  the  ozone  register  and  diagram,  which  in 
like  manner  cannot  possibly  be  copied  into  this  publi- 
cation. After  a  thoroughly  accurate  estimation  of  the 
amount  of  ozone  present  in  the  pure  air  of  different 
climates,  and  daring  the  various  atmospheric  changes  of 
each  climate,  we  shall  l;)e  in  a  position  to  attempt  an 
elucidation  of  the  following  and  inany  other  questions 
which  are  of  immense  interest  and  importance  to  the 
human  race : — 

1.  AVhat  are  all  the  sources  of  atmospheric  ozone  ? 

2.  How  is  it  formed,  and  in  what  circumstances  does  it 

arise  ? 

3.  What  is  its  precise  action  on  animals  and  plants  ? 

4.  Has  an  excess  or  deficiency  of  ozone  any  effect  on  the 

public  health  ? 
0.   If  so,  what  is  the  nature  of  that  influence  ? 

6.  "What  is  the  effect  of  the  presence   of  epidemics  on 

its  amount,  as  calculated  by  the  improved  ozonometric 
method  ? 

7.  Does   ozone   oxidize  one  only,  or  all   of  the   different 

kinds  of  organic  matter  found  in  the  air  ? 

The  elucidation  of  that  very  interesting  mystery 
respecting  the  supposed  relationship  betw^een  an  excess 
of  atmospheric  ozone  and  an  epidemic  of  influenza  is  one 
which  demands  special  attention,  because  of  the  fact  that 
an  excess  of  ozone  artificially  prepared  will  originate  a 
catarrh. 


ozonometi;y  357 

Peroxide  of  hydrogen. — The  best  method  for  the  estima-  pemxideof 
tion  of  this,  apait  from  the  other  air-purifiers,  involves  ''^^^'■"8^"- 
much  habour  in  its  performance   and  cannot  tlierefore  Ije 
here  described. 

Nitrous  acid  is  recognised  in  so  ready  a  manner  when  Nitrons 
present  in  the  air,  that  a  few  lines  must  be  devoted  to  a^*""" 
consideration  of  its  mode  of  detection. 

Griess,  who  recommended  the  employment  of  meta- 
phenylene  diamine  as  a  delicate  test  for  nitrous  acid  {vide 
page  110),  has  described  a  far  more  sensitive  test  for  this 
air  purifier.  His  later  test,  in  which  naphthylamine  is 
used,  renders  it  possible  to  distinguish  1  part  of  nitrogen 
in  1,0  0  0,0  0  0,0  0  0  parts  of  water.  Mr.  Eobert  Warrington 
recommends  ^  that  this  remarkably  deUcate  reaction  be 
applied  in  the  follow^ing  manner : — To  the  water  in  a  test 
tube  suspected  to  contain  nitrous  acid  are  added,  suc- 
cessively, one  drop  of  dilute  hydrochloric  acid  (1-4),  one 
drop  of  a  nearly  saturated  solution  of  sulphanilic  acid, 
and  one  drop  of  a  saturated  solution  of  hydrochloride  of 
naphthylamine.  Xitrous  acid  forms  with  the  sulphanilic 
acid  a  diazo-compound,  which  is  further  converted  by  the 
naphthylamine  into  a  body  of  a  rose  or  ruby  colour.  A 
mixture  of  freshly -distilled  water  and  these  reagents 
remains  colourless  when  left  in  a  half-filled  stoppered 
Ijottle,  but  when  exposed  to  the  air  in  au  open  vessel  may 
be  observed  to  deepen  in  tint  from  day  to  day  as  the 
absorption  of  nitrous  acid  proceeds.  Test  papers  are 
easily  prepared  by  soaking  small  strips  of  Swedish  filtering 
paper  in  a  solution,  made  by  dropping  a  drop  of  each  of 
the  reagents  into  about  two  fluid  drachms  of  distilled  water, 
and  then  drying  them  by  suspending  them  in  a  cupboard. 

^  "  Xote  on  the  appearance  of  nitrous  aeiil  during  the  eA'aporation  of 
water." — Juurnnl  Chemical  Socictij,  1S81,  p.  229. 


PAET    III 

SKETCH  OF  RELATION  BETWEEN  CERTAIN  METEOROLOGICAL 
VARIATIONS  IN  THE  CONDITION  OF  THE  AIR,  AND 
STATES  OF  HEALTH  AND  DISEASE 

In  the  consideration  of  "  all  influences  affecting,  or 
threatening  to  affect,  the  public  health  within  his  district," 
the  medical  officer  of  health  should  not  only  note  all 
sudden  and  great  changes  of  barometric  pressure  and 
heavy  falls  of  rain,  which  are  important  factors  in  the 
production  of  those  atmospheric  conditions  on  which 
movements  of  underground  air  and  water  depend,  but 
should  make  observations  on  those  climatic  and  topo- 
graphical peculiarities  which  are  likely  to  exert  any  action 
on  health.  The  value  of  his  observations  will  be  increased 
by  a  comparison  with  published  readings  taken  simul- 
taneously over  large  neighbouring  areas  and  by  a  study  of 
the  laws  that  govern  the  movements  of  the  air.  The 
variations  in  the  temperature,  humidity,  pressure,  and 
electric  state  of  the  atmosphere,  as  well  as  the  effects  of 
these  changes  on  the  moral  and  physical  condition  of 
nations  and  individuals,  form  a  most  extensive  field  of 
study,  and  one,  moreover,  of  the  highest  possible  interest. 
The  influence  of  climate  on  the  sanitary  condition  of  all 
animals,  and  especially  of  the  most  highly  organized  being 
in  the  scale  of  creation,  has  occupied  for  more  than  2000 
years,  and  still  engages,  the  attention  of  scientific  men. 


METEOROLOGICAL  VARIATIONS  359 

The  great  subject  of  weather  and  disease  has  been  worked 
at  ever  since  the  times  of  Pythagoras,  whose  doctrines 
were  supported  by  Hippocrates/  the  father  of  medicine. 
These  distinguished  philosophers  divided  nature  into  four 
qualities — viz.  cold  and  warmth,  dryness  and  moisture. 
They  considered  cold  with  moisture  to  be  hurtful,  and 
warmth  with  dryness  to  be  beneficial  qualities. 

The  three  following  rules  have  been  accepted  by  the 
few,  and  unrecognized  by  the  many,  for  hundreds  of 
years  : — 

1.  A  preternaturally  dry  air,  with  a  high  temperature, 
predisposes  to  the  development  of  fevers  and  intestinal 
disorders. 

2.  A  very  moist  atmosphere,  accompanied  by  a  low 
temperature,  is  apt  to  induce  bronchial  and  rheumatic 
affections. 

3.  A  very  dry  atmosphere,  when  associated  with  a 
low  temperature,  has  a  tendency  to  excite  inflammations 
of  the  respiratory  organs. 

The  labour  of  the  past  has  borne,  however,  some  little 
fruit,  for  we  are  obtaining  an  increased  knowledge  of  the 
influence  of  meteorological  conditions  on  health.  The 
bearings  on  health  of  the  disturbances  of  the  atmospheric 
sea  above  and  around  us,  occasioned  by  the  great  cyclonic 
and  anti-cyclonic  changes  throughout  the  world,  are  better 
understood,  thanks  to  the  telegrapliic  system  of  reporting 
the  approach,  direction,  and  rate  of  progress  of  storms,  and 
the  elucidation  of  the  laws  that  govern  their  motions. 
As  to  cyclones  in  which  the  winds  circulate  with  great  cycinnes. 
rapidity  around  and  towards  the  centre  or  point  of  loioest 
barometric  pressure,  from  which  rises  a  vast  ascending 
current,  physicians  with  meteorological  tastes  cannot  fail 
to  have  noticed  that  attacks  of  neuralgia  in  the  form  of 

^    Vide  "  ire  pi  aepiov,  vSaruv,  tottwv." 


360         METEOROLOGICAL    YAPJATIOXS    IX    RELATION 

migraine  aud  other  nervous  maladies  seem  often  to  recur 
at  the  approach  of  a  considerable  fall  of  the  barometer, 
especially  when  this  culminates  in  rain.  Dr.  AVeir 
Mitchell  gives  the  following  result  of  his  observations  on 
this  connection  in  the  case  of  a  Captain  Catlin,  U.S.A./ 
who  suffered  from  attacks  of  neuralgia  in  a  painful  stump: — 
"  It  was  rather  the  fact  of  a  storm,  or  the  disturbance  of 
pressure,  that  induced,  or  at  least  accompanied  pain,  than 
its  depth,  duration,  or  extent."  Dr.  Mitchell  adds,  "  Every 
storm  as  it  sweex:)S  across  the  continent .  of  America 
consists  of  a  vast  rain  area,  at  the  centre  of  w^hich  is  a 
moving  space  of  greatest  barometric  depression,  known  as 
the  storm  centre,  along  which  the  storm  moves  like  a 
bead  on  a  thread.  The  rain  usually  precedes  this  by  550 
to  600  miles,  but  before  and  around  the  rain  lies  a  belt 
which  may  be  called  the  neuralgic  margin  of  the  storm, 
which  precedes  the  rain  about  150  miles.  This  fact  is 
very  deceptive,  because  the  sufferer  may  be  on  the  far 
edge  of  the  storm  basin  of  barometric  depression,  aud 
seeing  nothing  of  the  rain,  yet  may  have  pain  due  to  the 
storm.  It  is  somewhat  interesting  to  figure  to  oneself 
thus  a  moving  area  of  rain  girdled  by  a  neuralgic  belt 
150  miles  wide,  within  which,  as  it  sweeps  along  in 
advance  of  the  storm,  there  prevail  in  the  hurt  and 
maimed  limbs  of  men  and  in  tender  nerves  and  rheumatic 
joints  renewed  torments  called  into  existence  by  the  stir 
and  perturbation  of  the  elements." 

Anti-cyclones,  or  periods  of  high  barometric  readings, 
in  which  the  winds  circulate  very  slowly  around  and  out 
from  the  centre  or  point  of  Ixvjhcst  pressure  of  the  baro- 
meter, which  is  filled  by  a  slowly  descending  current  from 
the  upper  regions,  last  longer  than  cyclones,  often  continu- 
ing for  many  days.  In  summer  they  are  characterized  by 
hot  sultry  weather  without  a  breeze,  and  in  Avinter  l)y  cold 
^  A/iierican  Jounutl  of  (he  Mcdiml  Sciences,  April  1S77, 


TO    STATES    OF    HEALTH    AND    DISEASE  oGl 

fogs.  The  former  climatic  condition  is  often  accompanied 
by  diarrhoea  and  cliolera,  whilst  the  latter  in  winter  is 
notorions  for  bronchial  and  catarrhal  affections. 

To  descend  from  the  general  to  the  particular,  we  know 
that,  as  regards  the  commencement  of  life,  the  offspring  of 
man  and  the  other  animals  born  in  the  cold  season  of  the 
year  has  a  higher  probability  of  life  during  the  first  year 
than  if  born  in  the  hot  season,  although  an  exposure  to 
excess  of  cold  is  highly  destructive  to  infancy ;  and  as 
regards  the  close  of  life,  that  the  mortality  by  cold  due 
to  age  doubles  every  nine  years  from  the  age  of  twenty, 
so  rapidly  does  the  power  of  resistance  to  cold  decline 
with  age. 

It  will  be  useful  to  consider :  first,  the  effects  of 
differences  of  temperature,  solar  radiation,  moisture,  and 
barometric  pressure,  direction  of  the  wind,  etc.,  on  health  ; 
and,  secondlij,  the  meteorological  conditions  which  appear 
to  favour  or  retard  the  development  of  those  diseases  that 
seem  to  be  influenced  most  bv  climatic  variations. 


The  Tem- 
perature of 
the  Air. 


CHAPTEE    XXXI 

1. THE     INFLUENCE     OF      DIFFERENCES     OF     TEMPEEATURE, 

SOLAR  RADIATION,  MOISTURE,  AND  BAROMETRIC 
PRESSURE  OF  THE  AIR,  DIRECTION  OF  THE  WIND, 
ETC.,  ON  HEALTH 

A.   The  Tein])erature  of  the  Air  =  A  ir  Warmth. 

The  average  mean  temperature  of  the  capitals  of  England, 
Scotland,  and  Ireland,  deduced  for  long  periods,  which  have 
been  published  by  Messrs.  Glaisher  and  Buchan,  are 
valuable,  and  they  give  at  a  glance  a  general  idea  of  the 
differences  between  the  temperature  of  these  countries. 


o  g 
eg 

c 

>-5 

< 

& 
S 

1-5 

< 

+2 

o 
O 

> 

o 

<D 
P 

Greenwich 

GO 

37-1 

39-0 

41-5 

46-6 

52-9 

59-1 

62-1 

01-3 

56-8 

60-1 

43-0 

39-9 

49-1 

Edinburgh 

30 

36-6 

37-9 

40-6 

44-8 

50-3 

55-6 

58-3 

57-5 

53-7 

47-5 

41-2 

38-6 

4(3-9 

Dublin 

36 

40-5 

41-2 

42-7 

47-2 

52-0 

57-1 

59-4 

58-9 

55-1 

50-3 

44-1 

42-7  J49-3 

The  following  dicta  may  be  regarded  as  aphorisms : — 

In  summer,  during  which  season  there  is  a  tendency 

to  intestinal  affections,  a  rise  of  mean  temperature  above 

the    average    increases    the    number    of    cases    and    the 

mortality  from  them. 

In  winter,  during  which  season  there  is  a  predisposi- 
tion to  lung  diseases,  a  fall  of  mean  temperature  below  the 
average  increases  the  number  of  cases  of,  and  the  mortality 
from,  these  affections. 


THE    TEMPERATUEE    OF    THE    AIR    AND    HEALTH      363 

When  the  temperature  in  London  falls  from  45°  to 
27°,  the  Eegistrar-General  calculates  that  about  400 
persons  perish  of  hroncJiitis. 

The  valuable  reports  of  the  Eegistrar-General  contain 
much  information  as  to  the  connection  of  mortality  from 
various  diseases  with  temperature.  As  his  reports  are 
quite  accessible  to  sanitarians,  I  shall  not  make  any 
further  quotation  from  his  calculations. 

Dr.  Ballard  concludes,^  from  a  comparative  study  of 
the  meteorological  observations  made  at  Greenwich  for 
the  six  years  from  1860-65,  and  on  the  amount  of 
parochial  sickness  in  the  parish  of  Islington  and  in  two 
large  metropolitan  dispensaries,  and  in  the  Pentonville 
convict  prison,  that — (1)  "  Comparative  warm  weather  is 
more  deleterious  to  public  health  in  the  colder  than  in 
the  warmer  half  of  the  year,"  which  is  certainly  opposed 
to  the  general  opinion  ;  (2)  "In  the  colder  months  of  the 
year  the  mean  temperature  is,  on  the  whole,  much  more 
important  as  a  condition  determining  the  absolute  quantity 
of  sickness  than  the  extent  of  the  diurnal  range,  and  that 
in  these  months  the  higher  the  mean  temperature  the 
more  important  is  the  influence  of  the  range;  (3)  In 
these  colder  months  a  low  range  is  more  injurious  to  public 
health  than  a  high  range,  whether  the  mean  temperature 
be  comparatively  high  or  comparatively  low,"  which  is  a 
conclusion  contrary  to  the  received  opinion  that  an  equable 
temperature  is  the  most  favourable  to  health  ;  (4)  "  That 
in  the  warmer  months  of  the  year  the  diurnal  range  of 
temperature  is,  on  the  whole,  more  important  as  a 
condition  determining  the  absolute  quantity  of  sick- 
ness than  the  mean  temperature ;  and  (5)  That,  in 
these  warmer  months,  a  high  diurnal  range  of  tempera- 

1  "  On  the  influence  of  some  of  the  more  important  elements  of  weather 
upon  the  absolute  amount  of  sickness." — British  Medical  Journal,  June 
12,  1869. 


364      THE    TEMPERATURE    OF    THE    AIll    AND    HEALTH 

ture  is  mucli  more  injurious  to  public  healtli  tliaii  a  Ljw 
range." 

Health  is  deleteriously  influenced  by  extreme  degrees 
of  cold,  unless  the  body  has  by  long  acclimatization 
become  inured  to  such  exposure.  In  the  Arctic  Expedition 
of  Sir  G.  ISTares,  the  crew  of  the  Alert  suffered  much  from 
the  extremely  low  temperature,  the  thermometer  being  in 
March  1876  so  low  that  — 73'7°  E.  w^as  registered.  Dr. 
Lansdell  states  ^  that  Yakutsk  in  North  Siberia  has  the 
credit  of  being  the  coldest  town  in  the  world.  Its  mean 
temperature  is  18-5°  F.  Between  December  17  and  Feb- 
ruary 18  of  each  year  the  cold  exceeds  —58°  F.  Mercury 
is  frozen  for  one-sixth  of  the  year.  So  accustomed  do 
natives  become  to  the  cold  that,  with  the  thermometer 
at  "unheard  of"  degrees  below  the  freezing  point,  the 
Yakute  women  with  bare  arms  stand  in  the  open-air 
markets  as  if  in  genial  spring.  A  man  wrapped  up  in 
his  pelisse  can  lie  without  inconvenience  on  the  snow, 
under  a  thin  tent,  when  the  temperature  of  the  air  is 
—30°  F.  He  also  states  that  the  maximum  temperature 
of  1877  at  Tomsk,  Siberia,  rose  at  1  p.m.  on  August  6  to 
106'9°,  and  the  minimum  temperature  reached  on  Christ- 
mas Day  8  3 "2°  below  zero,  and  that  at  Barnaul,  which 
lies  some  200  miles  to  the  south,  the  maximum  was  107'8°, 
and  the  minimum  84"8°  Ijelow  zero.  He  adds  that  small 
birds  sometimes  drop  dead  in  the  streets  from  cold. 

The  very  sensible  discomfort  and  illness  in  some, 
induced  by  sudden  and  extreme  ranges  of  temperature, 
as  much  at  times  as  30°  F.  or  40°  F.  in  a  few  minutes, 
must  often  press  itself  on  the  notice  of  the  health  officer. 
The  licaltliij  body  in  the  prime  of  life  shows  a  wonderful 
ability  to  adapt  itself,  not  only  to  great  difierences  of 
temperature  to  which  its  opposed  surfaces  or  extremities 
may  be  subjected,  but  to  extraordinary  ranges  of  tempera- 

1  Through  Siberia,  1883. 


THE    TEMPERATUKE    OF    THE    AlE    AND    HEAETH      3 Go 

ture,  as  extensive  even  as  72  degrees.  Akiricli,  in  the 
Western  Sledge  journey  from  the  Alert  in  April  1876, 
wrote,  "  The  air  is  very  cold,  and  the  sun  is  very  warm. 
The  thermometer  hanging  on  my  chest  registered  —12°  F., 
wdien  on  my  back  —30°  F."  The  very  young,  the  aged,  the 
feeble,  the  sickly  and  diseased,  are  generally  more  or  less 
disturbed  by  the  sudden  variations  of  our  fickle  climate, 
and  it  is  sometimes  found  almost  impossil.)le  to  provide 
against  the  rapid  alternations  of  heat  and  cold,  moisture 
and  dryness,  etc.,  with  suitable  clothing.  It  is  not  only  de- 
sirable, then,  to  oljserve  extreme  ranges  of  temperature,  but 
the  differences  between  the  temperature  of  the  earth  and 
of  the  air  4  feet  above  it.  Catarrhal  affections  are  some- 
times noticed  when  the  rays  of  the  sun  are  powerfully  felt, 
whilst  the  earth  is  at  the  same  time  exceedingly  cold. 

It  is  wise  to  bear  in  mind  the  occurrence  of  ex-"Coi(i^ 
ceptionally  cold  weather  on  certain  days  in  the  spring- 
months,  and  to  be  j^repared  for  it  with  clothing  of  an 
extra  warmth.  These  "  cold  spells  "  have  been  noticed 
over  all  parts  of  the  world,  and  were  pointed  out  long 
ago  Ijy  Ivaemtz  in  his  book  on  Meteorology.  Periods 
of  "  treacherous  weather "  at  this  season  of  the  year 
have  l)een  recognized  by  the  people  of  all  countries 
in  their  old  sayings.  They  occur  on  or  about  Feb- 
ruary 7  to  12,  April  10  to  14,  and  May  10  to  14. 
]\Ir.  Glaisher,  in  his  estimation  of  the  mean  daily 
range  of  temperature  at  the  Eoyal  Observatory,  Green- 
wich, during  the  sixty  years  from  1814  to  1873, 
found  ^  the  February  "  spell "  to  be  distinctly  visible,  but 
the  April  and  JMay  "  spells  "  to  be  situated  more  at  the 
commencement  of  those  months.  The  cold  "  snap "  of 
February  was  even  noted  by  the  pupils  of  Galileo.  The 
three  cold  days  of  April  are  called  in  Scotland  and  the 

^  Quarterhj  Journal  of  Meteorological  Socief>j,  vol.   iii.,  Xew  Series,  Xo. 
20,  October  1876. 


366      THE    TEMPERATURE    OF    THE    AIR    AND    HEALTH 

North  of  England  "  the  borrowing  days,"  as  they  are  sup- 
posed to  be  lent  by  the  colder  month  of  March. 

Madler-^  examined  the  mean  temperature  of  May  in 
Berlin  for  eighty-six  years,  and  found  a  retrogression  of 
temperature  amounting  to  2 '2°  F.  from  May  11  to  13. 

Cool  rainy  summers  are  generally  periods  of  low 
mortality.  Cold  winters  and  hot  summers,  although 
agreeable  to  the  strong  and  healthy,  are  fatal  in  their 
effects  on  the  general  population.  Intestinal  disorders 
kill  in  hot  summers,  whilst  pulmonary  affections  destroy 
life  in  cold  winters.  Dr.  Eichardson  states:^  "that,  (1) 
the  phenomena  of  catarrhs  or  colds  are  confined  witliin  a 
range  of  temperature  extending  from  a  mean  of  41°  F. 
to  the  extreme  cold  of  the  Arctic  chmate ;  (2)  yellow 
fever  can  only  continue  in  parts  of  the  earth  where  there 
is  a  mean  temperature  above  68°  F.;  (3)  typhus  fever 
flourishes  only  in  regions  having  a  range  of  temperature 
lying  between  40°  F.  and  62°  F.;  and  (4)  the  phenomena 
of  phthisis  pulmonalis  are  so  limited  by  a  given  degree 
of  cold  that  they  cannot  exist  in  the  Hebrides,  Faroe 
Isles,  Iceland,  and  the  Arctic  Eegions."  Some  years  ago  a 
considerable  discussion  took  place  in  the  medical  journals 
as  to  whether  phthisis  pulmonalis  did  or  did  not  occur  in 
Iceland,  the  result  of  which  terminated  in  the  production  of 
evidence  which  showed  that  it  is  found  there,  and  that  the 
hilly  tablelands  of  Mexico  are  the  only  parts  of  the  civi- 
lized (?)  world  where  the  disease  is  unknown (-yic^c  page  280). 
Is  it  not  probable,  in  view  of  recent  bacteriological  researches, 
that  isolation  has  much  to  do  with  the  immunity  enjoyed  by 
the  inhabitants  of  these  islands  and  out-of-the-way  places  ? 

As  regards  the  climate  of  this  country  it  has  been 
recommended :  ^ — 

^   Verhandlung  cles  Vcreins  zur  Beford  des  Garteiibanes,  1834. 

^  Diseases  of  Modern  Life. 

3  "  The  effect  of  cold  on  children." — Brit.  Med.  Journal,  Dec.  25,  1875. 


THE    SOLAR    RADIATION  367 

1.  That  no  child  too  young  to  walk  or  run  should  be 

taken  out  of  doors  when  the  external  temperature 
is  below  50°  F.^ 

2.  That  the  rooms  in  which  children  live  and  sleep 

should  never  be  below  58°  F.;  and 

3.  That  the  dayroom  should  be  three  or  four  degrees 

warmer  than  the  bedroom. 
The  relation  between  certain  varieties  of  coup  de  soleil 
or  heat  apoplexy,  as  well  as  other  ajffections,  and  the 
indications  of  solar  and  terrestrial  radiation  thermometers, 
is  a  subject  that,  if  worked  at,  will  probably  yield  valuable 
results. 

B.    TJie  Solar  Badiation. 

The  sun -warmth  is  a  factor  in  the  production  ofsun- 
climate  of  considerable  importance  to  health,  and  is^^^'°^ 
estimated  by  the  means  of  a  solar  radiation  thermometer 
{vide  page  414).  The  space  at  my  disposal  will  not  permit 
me  to  dwell  on  its  relation  to  the  duration  of  sunshine,  as 
registered  by  the  several  ingenious  arrangements  for  its 
measurement,  but  will  only  allow  me  to  direct  attention 
en  passant  to  the  very  suggestive  influence  on  life  and 
growth,  shown  by  the  relation  between  the  amount  of 
sunshine  and  the  yield  of  hay  and  other  vegetable  crops, 
the  abundance  during  years  of  little  sunshine  being 
compensated  for  by  a  deficiency  in  weight. 

Dr.  Frankland  has  pointed  out^  that  the  sun-warmth 
is  influenced :  (1)  by  the  colour  of  the  soil,  and  our 
other  surroundings  and  their  consequent  absorbent  power  ; 

1  The  No.  1  recommendation  is  too  stringent,  and  requires  the  addition 
of  the  words,  ' '  unless  carried  in  the  arms  of  an  adult,  so  as  to  derive 
warmth  from  an  external  source."  On  several  occasions  have  young 
children  come  under  my  charge  who  have  been  exposed  in  perambulators 
to  great  cold,  in  whom  a  complete  cessation  of  the  flow  of  bile  into  the 
intestinal  canal  has  occurred. 

2  "The  Climate  of  Town  and  Countrj^,"  in  Nineteenth  Century. 
July  1882, 


368  HYGEOMETRIC    STATE    OF 

(2)  By  reflection  from  land  (snowfields  or  chalk-pits)  or 
water  ;  and  (3)  by  the  amount  of  watery  "S'apour  in  the  air. 
"  The  nearer  the  colour  of  the  ground  approaches  to  white, 
the  greater  will  Ije  the  sun's  warmth  and  the  cooler  the 
air ;  whilst  the  darker  the  colour,  the  warmer  will  be  the 
air,  and  the  less  will  the  heat  of  solar  radiation  be 
felt.  The  darker  the  colour  of  our  houses  the  cooler  the 
streets,  and  the  hotter  the  rooms  during  sunshine.  The 
lighter  the  colour  of  the  houses,  the  hotter  the  streets  and 
the  cooler  the  rooms."  The  dark,  distinguished  from  the 
luminous,  heat  rays  are  sifted  out  of  tlie  air  by  the  watery 
Aapour  in  its  low^er  strata,  hence  the  higher  we  ascend 
into  the  air  the  greater  is  the  sun's  warmth. 

He  points  out  that  the  sun's  warmth,  unlike  the  air 
temperature,  is  greater  in  Norway  than  at  the  equator, 
because  the  air  is  colder,  and  therefore  drier,  in  the  Arctic 
than  in  the  hot  reo'ions  of  the  world. 

o 

Vapour  in  a  cubic  foot  of  air.     ; 
Grains. 

1-8 
15-2 

Arctic  voyagers  have  stated  that,  with  the  temperature 
in  the  shade  far  below  freezing-point,  the  pitch  will  boil 
in  the  seams  of  the  vessel  where  it  is  exposed  to  the  sun. 

Dr.  Frankland  has  drawn  a  strong  contrast  between 
the  sensations  experienced  wdieii  he  was  exposed  to  the 
following  opposite  climatic  conditions  : — 


Di-y  liulb. 

Wet  bulb 

36 

33 

96 

93 

Bellaggio 
Summit  of  the 
Diavolezza  Pass 

Sun  Wanntli.  Air  Warnitli. 

Ktiiiarks. 

72° 
107° 

83° 
43° 

Heat  most  oppressive. 

Delicious  sensation  of  coolness. 

1 

He  omits  all  reference,  however,  to  the  influence  of 
the  hygrometric  condition  of  the  air,  Avhicli  was  probably 
four  or  five  tmies  RTeater  at  the  former  than   at  the  latter 


THE    AIR   AND    HEALTH  369 

station,   and   which    has   much    to    do   with    the    sultry 
character  of  heat. 

C.   The  Hygrometric  State  of  the  Air. 

Whilst  the  air  is  never  without  some  moisture,  the  The 
amount  present  in  the  air  is  largely  due  to  its  tempera- ™g^^^_''^° 
ture,  the  capacity  for  retaining  moisture  in  an  invisible 
gaseous  form  being  greater  when  the  temperature  is  high 
than  when  it  is  low. 

The  aching  of  rheumatic  joints  and  of  corns,  the 
extraordinary  noises  that  sometimes  proceed  from  chairs 
and  tables,  and  the  condition  of  certain  epithelial  struc- 
tures, such  as  the  hair  and  skin,  are  often  signs  to  the 
public  of  the  approach  of  rain,  all  being  the  result  of  an 
excess  of  humidity  in  the  air,  due  to  the  great  alterations 
in  size  which  fibrous,  epithelial,  and  ligneous  bodies  undergo 
by  the  addition  or  subtraction  of  moisture.  How  cleverly 
did  the  great  Jenner  embody  in  a  few  lines  of  verse, 
"  On  the  Signs  of  Eain,"  the  effects  of  this  atmospheric 

change — 

"  Hark  !  liow  the  chairs  and  tables  crack, 
Old  Betty's  joints  are  on  the  rack." 

The  decrease  of  the  pressure  of  the  air  which  generally 
accompanies  an  excessive  hygrometric  condition  has  doubt- 
less, however,  much  to  do  with  the  painful  condition  of 
that  old  lady's  joints.  "We  know  but  little  of  the 
influences  of  varying  degrees  of  humidity  of  the  air  on 
animal  life.  It  is  unquestionable  that  an  excess  or 
deficiency  of  the  normal  amount  of  moisture  in  the  air 
exerts  a  very  decided  action  on  the  state  of  the  public 
health.  People  in  health  merely  feel  slightly  depressed 
when  the  air  is  rather  damp,  and  somewhat  ii'ritable 
when  it  is  unusually  dry,  but  to  invalids  even  a  change 
of  two  or  three  per  cent  in  the  humidity  is  perceptible. 
An  excess  is  the  more  prejudicial,  because  aqueous  vapour 

2  B 


370  HYGEOMETEIC    STATE    OF 

possesses  a  powerful  affinity  for  organic  matter,  and  serves 
both  to  preserve  and  diffuse  it.  We  all  of  us  have  fre- 
quently experienced  the  enervating  effects  of  a  fog,  which 
has  been  termed  "  half  an  air  and  half  a  water,"  and  the 
return  of  our  usual  mental  and  bodily  vigour  on  its 
removal.  When  we  remember  that  all  depressing  agents 
predispose  to  disease,  the  subject  of  humidity  in  relation 
to  hygiene,  connected  as  it  is  so  intimately  with  that  of 
climate,  cannot  be  too  diligently  examined. 

Insular  climates,  in  the  temperate  latitudes,  are 
necessarily  humid  to  a  certain  extent,  especially  if  the 
temperature  is  low.  Wlien  there  is  in  addition  an 
excessive  rainfall,  a  damp,  foggy,  and  relaxing  climate  is 
produced,  which  often  exercises  an  injurious  influence  on 
the  health  of  those  unacchmatized  to  it.  The  voice  of 
Grassini  was  reduced  nearly  an  octave  by  the  relaxing 
effect  of  the  air  of  this  country.  Her  vocal  organs  were 
restored,  however,  to  their  normal  condition  on  her  return 
to  the  drier  climate  of  Italy, 
Female  The  vicw  has  been  expressed  that  the  degree  of 
^^"  ^'  moisture  of  the  air  is  intimately  associated  with  the 
degree  of  beauty  in  the  human  female,  and  especially 
with  its  duration.  The  average  hygrometric  state  of  the 
air  is  but  one  of  the  many  factors  concerned,  which,  by 
their  union,  form  the  climate  of  a  country,  by  which 
the  female  body  is  undoubtedly  influenced  to  a  consider- 
able extent  in  its  development.  Temperature  indubitably 
exerts  an  effect  which  is  perhaps  scarcely  if  at  all  inferior. 
Warm  moist  climates,  in  the  temperate  regions  of  the 
earth,  have  been  considered  to  produce  more  beautiful 
women,  whose  beauty  endures  longer  than  countries 
possessing  different  qualities  of  climate.  As  we  leave 
the  temperate  climes  for  the  sunny  south,  where  develop- 
ment is  more  rapid,  and  the  period  of  puberty  earlier,  we 
notice  that  female  beauty  is  very  evanescent,  and  is  soon 


THE    AIE    AND    HEALTH  371 

on  the  wane.  As  the  temperate  latitudes  are  left  for  the 
northern,  colder,  and  drier  climates,  there  is  a  coarse- 
ness, and  want  of  the  softness  and  delicacy  so  charac- 
teristic of  the  women  of  the  south.  Modes  of  life, 
differences  of  race  and  character,  as  well  as  the  kind 
of  climate,  have,  of  course,  some  considerable  action 
on  the  grace  and  loveliness  of  the  female.  This  sulj- 
ject  is  one  of  great  magnitude,  on  which  there  will 
necessarily  be  a  divergence  of  opinion,  as  the  question  of 
taste  is  very  much  involved.  I  only  allude  to  it  as  one 
deserving  of  thought. 

An  excess  of  aqueous  vapour  in  the  atmosphere  has  An  excess, 
not  only  a  depressing  effect  on  the  nervous  system,  but 
it  interferes  with  the  cutaneous  and  pulmonary  exhala- 
tions. If  the  temperature  is  high  (65°  to  80°  F.), 
saturated  air  is  sultry  and  oppressive.  If  low  {e.g.,  a 
Scotch  mist  of  36°  F.),  its  chilling  influence  penetrates  all 
clothing.  At  least  one  half  of  the  patients  who  apply 
for  relief  during  the  winter  months  to  the  physicians  of 
the  metropolitan  and  provincial  hospitals  of  this  country 
are  afflicted  with  colds,  coughs,  bronchial  and  rheumatic 
affections.  The  prevalence  of  these  disorders  at  this 
season  is,  without  a  doubt,  due  partly  to  the  coldness  in 
association  with  the  excessive  moisture  of  our  very  change^ 
able  climate.  Above  80°  R,  air  of  excessive  humidity 
becomes  injurious  ;  and  it  has  been  doubted  as  to  whether 
life  can  be  prolonged  in  such  air  at  a  temperature  between 
90°  F.  and  100°  F. 

A  very  dry  air  is  considered  by  some  as  less  deleterious  a  defici- 
to  health  than  a  very  moist  air.  Assistant- Surgeons  ^""^^^^ 
Lauderdale  and  Eoss,  in  a  report  relative  to  Fort  Yuma, 
California,  write  :  ^ — "With  the  thermometer  at  105°  F., 
the  skin  becomes  dry  and  hard,  and  the  hair  crisp,  and 
furniture  falls  to  pieces.  Newspapers,  if  roughly  handled, 
^  Quarterly  Journal  of  Science,  April  1878. 


3  /  2  HYGROMETEIC    STATE    OF 

break.  Egcjs  that  have  been  on  hand  for  a  few  weeks 
lose  their  watery  contents  by  evaporation,  and  the  re- 
mainder is  tough  and  hard.  A  temperature  of  100°  F. 
may  exist  for  weeks  in  succession,  and  there  will  be  no 
additional  cases  of  sickness  in  consequence.  We  have 
none  of  the  malarial  diseases." 

Dr.  Ballard's  ^  inferences  as  to  the  effect  of  variations 
in  atmospheric  moisture,  as  represented  by  the  readings 
of  the  hygrometer,  and  the  estimation  of  the  rainfall  on 
the  public  health  of  a  portion  of  London,  are  thus  given 
by  him : — 

"  1.  That  in  the  colder  months  of  the  year  the  mean 
temperature  is,  on  the  whole,  more  important  as  a  con- 
dition determining  the  absolute  quantity  of  sickness  than 
the  amount  of  accompanying  atmospheric  moisture.  2. 
That  in  the  warmer  months  of  the  year,  on  the  other 
hand,  the  amount  of  atmospheric  moisture  is  more  im- 
portant as  a  condition  determining  the  absolute  quantity 
of  sickness  than  the  mean  temperature.  3.  That,  both  in 
the  colder  and  warmer  seasons  of  the  year,  a  compara- 
tively dry  condition  (for  the  season)  of  the  atmosphere  is 
more  damaging  to  public  health  than  a  comparatively 
moist  condition  of  the  atmosphere.  The  amount  of 
rainfall  is  more  important  at  comparatively  low  than 
at  comparatively  high  temperatures,  in  regulating  the 
absolute  quantity  of  sickness." 

Writers  on  cholera  in  India  have  pointed  out  the 
coincidence  of  maximal  rainfall  and  minimal  cholera. 

The  artificial  climates  which  we  manufacture  in  our 
houses  and  public  buildings  are  far  more  deleterious  to 
health  than  any  atmospheric  vicissitudes  as  to  moisture. 
The  air  of  The  air  of  our  rooms  has  a  tendency  to  be  preternaturally 
dry,  and  when  so  is  often  oppressive  and  unwholesome. 
The  degree  of  moisture  of  air  is  shown  by  the  hygrometer, 

1  Op.  cit. 


our  rooms. 


THE    AIR    AND    HEALTH  373 

wliicli  consists  of  two  thermometers,  one  the  dry  bulb, 
and  the  other  (covered  with  muslin  and  attached  by  a 
lamp  wick  to  a  feeder  of  water)  the  wet  bulb.  The 
difference  between  these  bulbs  is  about  five  or  six  degrees 
in  a  healthful  atmosphere.  In  rooms  warmed  by  radiant 
heat  it  reaches  often  eight  degrees ;  whilst  in  rooms 
heated  by  hot  air  a  difference  of  fifteen  to  seventeen 
degrees  is  often  noticed,  which  is  unwholesome  and  un- 
pleasant. Although  so  many  different  kinds  of  stoves  and 
other  appliances,  such  as  hot  water  pipes,  etc.,  for  heating 
rooms  have  been  devised,  that  important  point  seems 
nearly  always  to  have  been  overlooked,  namely,  the 
maintenance  of  a  healthful  amount  of  moisture  in  the  air. 

I  have  seen  pans  of  water  placed  on  iron  stoves  to 
counteract  the  unpleasant  effects  caused  by  the  dryness 
of  the  air,  and  have  seen  the  water  steaming,  and  even 
boiling.  In  such  an  apartment  there  was  an  excess  of 
moisture  in  the  air  which  made  me  feel  very  uncom- 
fortable, creating  the  disagreeable  sensation  which  one 
experiences  on  entering  the  house  of  a  laundress ;  the 
hygrometer  in  such  a  case  giving  a  difference  of  onlj 
one  or  two  degrees,  showing  that  the  air  was  almost 
saturated  with  watery  vapour  in  an  invisible  form. 

The  air  sometimes  becomes  almost  saturated  with  the 
aqueous  vapour  that  proceeds  from  the  pulmonary  and 
cutaneous  surfaces  in  crowded  halls  or  rooms.  Prof. 
Sanders  relates  ^  an  anecdote,  narrated  to  him  by  a  Eussian 
officer,  of  the  production  of  a  shower  of  snow  that  fell  on 
the  audience  in  a  concert-room  by  the  sudden  opening,  in 
very  cold  weather,  of  a  window,  for  purposes  of  ventilation. 

Even  now,  when  the  study  of  health  and  the  influ- 
ences which  deteriorate  and  promote  it,  coupled  with  the 
prevention  of  disease,  are  the  great  subjects  of  the  day, 
rivalling  in  interest  the  kindred  one  of  the  cure  of  disease, 
^  Handhuch  der  offcntlichcn  Gesundhcitspflcge. 


374  THE    PRESSURE    OF    THE    AIR 

there  seems  a  complete  ignorance  or  apathy  in  regard  to 
this  subject  amongst  physicians  and  leading  architects. 
The  modern  On  visiting  somc  ycars  ago  the  completed  portion  of 
holpTtai.  ^^®  New  Edinburgh  Eoyal  Infirmary,  which  is  fitted  with 
all  the  most  approved  and  recent  appliances  for  heating, 
ventilation,  etc.,  and  which  is  considered  to  take  the  place, 
previously  occupied  in  turn  by  St.  Thomas'  Hospital,  London, 
and  the  Lariboisiere  and  Hopital  de  Menilmontant  in  Paris, 
of  the  modern  pattern  hospital,  I  was  astonished  to  find 
that  no  provision  whatever  existed  for  supplying  moisture 
to  the  air  dried  by  the  coils  of  hot  water  pipes  that  are 
seen  in  so  many  places.  If  gardeners  were  to  treat  their 
greenhouse  plants  thus,  healthy  life  and  growth  would  be 
impossible.  Horticulturists  always  furnish  their  hot 
water  pipes  with  long  troughs,  filled  with  water,  that  rest 
on  the  pipes,  and  thus  maintain  an  artificial  climate, 
closely  resembling  that  to  which  the  plants  have  been 
accustomed,  in  which  air  is  enabled  to  lick  up  as  much 
water  as  its  temperature  will  permit. 


i).    Tlie  Pressure  of  the  Air. 

Tiie  There  is  a  strong  popular  belief  that  old  wounds,  in- 

theAir.  jurics,  discascd  bones,  and  rheumatic  joints  are  the  seat 
of  discomfort,  or  even  pain,  on  the  approach  of  a  storm, 
which,  speaking  generally,  means  in  this  country  a  sudden 
decrease  of  at  least  ^  inch  of  the  mercurial  column. 
Eichardson  and  others  tell  us  that  when  the  body  is  ex- 
posed to  low  barometric  pressure  there  is  a  tendency  to 
exudation  of  fluid  from  wounded  surfaces,  a  feebleness  in 
the  healing  of  wounds,  a  susceptibility  to  disturbance  in 
the  body  generally,  and  a  proneness  to  the  production  of 
secondary  fever  by  the  absorption  of  discharges  which 
have  undergone  some  decomposition.  The  outcome  of 
these  facts  has  been  the  establishment  of  the  law  that  no 


A\D    A    STATE    OF    HEALTH  375 

important  surgical  operation  should  be  performed  when 
the  barometer  is  low,  or  when  it  is  steadily  falling.  The 
principal  effect  of  diminished  pressure  of  the  atmosphere 
is  distension  of  the  capillaries.  "We  all  recognize,  as  one 
of  the  exciting  causes  of  apoplectic  seizures,  a  rapid 
diminution  of  atmospheric  pressure  producing  a  sudden 
capillary  engorgement.  Dr.  M.  A.  Veeder,  of  Lyons,  New 
York,  suggests  that  there  is  a  difficulty  in  the  adjustment 
of  the  volume  and  rate  of  the  circulation  of  the  blood  to 
the  varying  atmospheric  pressure  upon  the  surface  of  the 
body,  and  consequent  unusual  strain  on  the  weakened 
bloodvessels.  Dr.  Murray,  of  Forfar,  is  in  the  habit  of 
advising  his  elderly  patients  who  have  weak  hearts  and 
degenerated  arteries  to  observe  the  strictest  moderation  in 
eating,  drinking,  and  in  mental  and  physical  exertion, 
when  the  barometer  suddenly  rises  and  falls.  Mr.  Wood, 
of  King's  College  Hospital,  introduced  the  question  in  the 
British  Medical  Journal  in  the  spring  of  1872,  as  to  why 
cases  of  joint  disease  are  invariably  worse  during  the 
warm,  moist  days  of  winter  ?  It  was  curious  that  his 
attention  should  have  just  at  that  time  been  pai'ticularly 
called  to  the  connection,  for  the  pressure  of  the  air  in 
London  had  been  less  early  in  that  year  than  had  been 
noted  for  nearly  thirty  years.  Indeed,  it  was  stated,  on 
the  authority  of  the  editor  of  the  Meteorological  Magazine, 
that  only  on  two  occasions  during  the  present  century  had 
the  barometer  been  so  low  as  on  January  24,  1872.  An 
exacerbation  of  the  symptoms  in  cases  of  joint  disease 
may  be  due  to  low  barometric  pressure,  acting  in  a 
manner  which  may  be  thus  explained : — In  the  solid, 
inelastic  articular  expansions  of  the  bones,  which  are  sur- 
rounded by  firm  inextensile  textures,  forming  the  joints, 
the  minute  nerves,  shown  by  Kolliker  and  others  to  per- 
meate the  cancellous  and  compact  structures  in  company 
with  vessels,  are  pressed  by  these  vessels,  when  enlarged. 


376  THE    PRESSURE    OF    THE    AIR 

against  the  unyielding  walls  of  th.e  channels  through 
which  they  pass.  Although  the  nerves  of  bones  do  not 
generally  afford  healthy  individuals  any  conscious  sensa- 
tions, yet,  in  diseases  of  the  joints,  the  bones,  when 
congested  or  the  seat  of  inflammation,  become  painful. 
Tissues,  not  supplied  with  rigid  canals  like  bone,  yield  to 
pressure  during  any  temporary  increase  in  the  size  of  the 
minute  vessels.  In  such  tissues,  vascular  distension,  from 
a  diminution  of  the  pressure  of  the  air,  is  unassociated 
with  pain,  because  the  nerves  accompanying  the  vessels 
are  uninterfered  with.  Low  barometric  pressure  and  an 
excess  of  humidity  of  the  air  offer  conditions  most  unfav- 
ourable for  the  removal  of  heat  by  evaporation  and 
radiation  from  a  congested  or  an  inflamed  joint.  Teeth, 
which  have  a  nutrient  system  very  similar  to  that  pos- 
sessed by  bone,  become  painful  when  the  pressure  of  the 
air  is  suddenly  lessened,  for  the  same  reason.  The  nerves 
of  the  tooth  being  in  a  morbid  condition  from  caries,  are 
temporarily  irritated  by  the  capillary  enlargement.  How 
is  it  that  joints  which  are  not  diseased  ache  when  the 
barometer  is  low  ?  I  am  not  aware  that  this  occurs  in 
the  young  and  healthy.  Experience  teaches  us  that  old 
rheumatic  people  often  complain  of  this  s}Tuptom.  Such 
persons,  whose  joints  are  not  in  a  perfectly  healthy  state, 
are  generally  worse  during  damp  weather,  in  consequence, 
I  presume,  of  imperfect  elimination  by  the  skin,  and  of 
the  lowering  of  the  vitality  of  parts  (whereby  the  action 
of  a  morbid  condition  is  favoured), — changes  undoubtedly 
induced  by  the  meteorological  conditions,  the  effects  of 
which  we  have  been  considering.  It  has  for  a  long  time 
been  held  that  increased  atmospheric  pressure  artificially 
applied  exercises  an  ancemiating  and  compressing  action 
in  the  peripheric  tissues  ;  that  it  diminishes  the  frequency 
of  the  pulse  and  the  calibre  of  the  small  vessels  generally, 
thus  increasiner  the  obstacles  which  the  vascular  walls 


AND    A    STATE    OF    HEALTH  377 

oppose  to  the  current  of  blood  from  the  heart.  M.  Vivenot 
states  that  this  dmiinution  iu  the  size  of  the  vessels  may- 
be seen  on  the  conjunctiva,  on  the  ear  of  the  rabbit,  and 
on  the  vessels  of  the  retina,  and  that  rarified  air  produces 
contrary  effects  {VircJiows  Archiv.  1866).  The  hsemorr- 
liages  and  peripheric  congestions  observed  in  aeronauts, 
and  in  divers  and  miners,  are  in  this  mechanical  manner 
accounted  for.  M.  Bert^  and  Forlanini^  have  impugned  the 
correctness  of  this  view,  and  state  that  the  calibre  of  the  cap- 
illaries does  not  undergo  change  under  the  action  of  com- 
pressed air.  The  therapeutic  employment  of  compressed  air, 
which  is  given  at  a  pressure  of  from  1  to  1 0  atmospheres,  in 
bronchitis,  asthma,  and  other  affections,  is  now  a  recognized 
mode  of  treatment,  as,  for  example,  at  Ben  Ehydding,  in 
Yorkshire,  and  at  some  establishments  in  France  and 
Germany.  The  physiological  effects  are  said  to  be  the 
following : — 1.  Augmentation  in  the  amplitude  of  the 
inspirations  ;  2.  Diminution  in  the  number  of  respirations 
in  a  given  time ;  3.  Prolongation  of  the  expiratory  act ; 
4.  Gradual  augmentation  of  the  capacity  of  the  lungs  ;  5. 
Superoxygenation  of  the  blood,  increased  activity  of  the 
organic  combustion,  and  elevation  of  temperature. 

The  effects  of  diminished  pressure  of  the  air  are  an 
increase  in  frequency  of  the  respiratory  and  circulatory 
acts,  and  a  reduction  of  the  activity  of  the  nutritive  pro- 
cesses, as  shown  by  the  amount  of  urea  eliminated. 

The  treatment  of  certain  pulmonary  diseases  by  com- 
pressed and  rarified  air  as  a  substitute  for  change  of 
climate  has  been  introduced  into  the  United  States  by 
Dr.  H.  E.  Williams  under  the  somewhat  ponderous  title 
of  "  Pneumatic  Differentiation,"  as  a  new  method.^ 

The  subject  of  the   effects  on  health  of  changes  in 

1  Comptes  Rendus,  August  19  and  August  26,  1872. 

2  Gazzetta  Medica  Italiana,  Lonibardi,  March  31,  1877. 

3  Kcio  York  Medical  Record,  January  17,  1885. 


378  DIEECTION    OF    WIND    AND    HEALTH 

atmospheric  pressure  ^  should  be  more  clearly  ascertained, 
and  it  offers  a  wide  and  encouraging  field  for  exploration. 

]\Ieteorological  vicissitudes  appear  to  exert  an  influence 
on  nervous  maladies.  Persons  whose  stumps  of  amputated 
limbs  are  painful  sometimes  get  into  a  morbid  and 
hysterical  state  of  mind  ;  and  in  their  prospective  study 
of  their  discomforts,  this  hyperaesthetic  condition  gives 
rise  to  fanciful  imaginary  ideas. 

It  is  the  experience  of  those  who  have  the  care  of  the 
insane  that  a  sudden  and  great  decrease  in  atmospheric 
pressure  is  generally  accompanied  by  an  increased  excita- 
bility, more  apparent  amongst  some  forms  of  mental 
disease  than  others.  The  late  Dr.  Day,  of  Geelong, 
connected "  an  epidemic  of  suicide  which  prevailed  in 
Australia  in  1872  with  a  period  of  low  barometric  pres- 
sure. Dr.  Eansome  has  observed  ^  that  a  high  degree  of 
atmospheric  pressure  is  favourable  to  the  production  of 
neuralgias. 

E.   The  Direction  of  the  Wind. 

The  West    and    north-west    winds    are    considered    more 

the  Wind,  favourable  to  health  than  south  and  south-west  winds, 
which  are  generally  warm  and  soothing  to  invalids,  and 
others  with  an  irritated  pulmonary  surface.  North  and 
north-east  are  not  considered  unfavourable  to  health,  and 
are  generally  enjoyed  by  those  who  are  robust.  The  east 
winds  of  spring  are  proverbially  deleterious,  except  to  the 
strong  and  healthy,  by  reason  of  their  coldness  and 
dryness. 

The  heat  of  the  sun  is  greater  when  the  air  is   dry 

■^  Vide  Effets  Physiologiques  et  Ap2^lications  TM^'ajxutiques  de  I'Air 
Comprime,  by  Dr.  J.  A.  Fontaiue,  1877. 

^  Australian  Medical  Journal,  November  1872. 

^  "  On  Atmosiaheric  Pressure  and  the  Direction  of  the  Wind  in  relation 
to  Disease,"  read  before  the  Manchester  Philosophical  Society. 


DIRECTION    OF    WIND    AND    HEALTH 


379 


than  when  it  is  moist,  for  the  humidity  of  the  air  acts 
as  a  screen  to  the  sun's  rays.  A  sudden  exposure  of  the 
body  to  extremes  of  temperature,  such  as  are  experienced 
when  passing  out  of  the  oppressively  hot  sunshine  into 
the  icy  cold  shade,  is  injurious  to  the  weakly,  for  it  is 
unable  to  accommodate  itself  readily  to  the  rapid  transition. 

The  dry  east  winds  are  not  complained  of  so  much  if 
they  blow  in  February  as  in  March  or  April,  because  we 
do  not  receive  so  much  heat  from  the  sun  in  the  former 
as  in  the  latter  months,  and  are  not  therefore  exposed  to 
the  same  extremes  of  temperature. 

East  winds  have  been  especially  connected  with  the 
production  of  neuralgic  affections,  and  the  moist  warm 
relaxing  winds  from  the  south-west  have  to  a  less  extent 
been  blamed. 

Dr.  W.  Mitchell  found  that  of  50  cases  of  amputation 
of  limbs  less  than  half  felt  unusual  sensations  upon  the 
coming  of  or  during  an  east  wind.  Of  the  rest,  two-thirds 
insisted  on  their  power  to  predict  such  a  change  of 
weather,  but  said  they  were  unaffected  by  a  thunderstorm 
or  by  rain  coming  from  the  south. 

Dr.  Ballard's  observations,  to  which  allusion  has  already 
been  made,^  lead  him  to  believe  that  westerly,  southerly,  and 
south-westerly  winds  are  associated  with  a  larger  amount 
of  sickness  than  northerly  and  north-easterly  winds. 


No.  of 
Weeks. 

Sum  of  Sickness  in 
new  cases. 

Mean. 

W.S.S. 

2 

984 

497 

s.w. 

103 

48,550 

471 

w. 

7 

3273 

467 

N.W. 

5 

2312 

462 

N. 

3 

1382 

460 

Var. 

47 

21,660 

460 

N.E. 

33 

14,952 

453 

N.N.E. 

4 

1790 

447 

Op.  cif. 


CHAPTEE    XXXII 

2. THE   METEOEOLOGICAL    CONDITIONS    WHICH    APPEAR    TO 

FAVOUE    OR   RETARD    THE    DEVELOPMENT  OF   CERTAIN 
DISEASES 

The  influence  of  season  is  recognized  by  physicians  in 
the  treatment  of  disease,  and  by  surgeons  in  the  repair  of 
injuries.  When  aU  animal  and  vegetable  life  exhibits 
evidence  of  growth  in  spring,  the  most  intractable  forms 
of  disease  will  sometimes  yield  to  treatment.  This  \is 
medicatrix  nature  is  especially  seen  in  the  young,  but  is 
also  frequently  noticed  in  the  aged. 

It  will  be  useful  to  dwell  briefly  on  the  relative 
prevalence  of  certain  diseases  during  the  several  months 
and  seasons  of  the  year,  in  order  to  ascertain  the  influence 
exerted  on  them  by  meteorological  changes. 

1.  Surgical  fever  and  shock  after  operations. 

2.  Smallpox. 

3.  Measles. 

4.  "VA^ooping  cough. 

5.  Scarlet  fever. 

6.  Fever. 

C  Diarrhoea. 

7.  <  Dysentery. 
(  Cholera. 

8.  Bronchitis,  pneumonia,  and  asthma. 


SEASONAL    METEOROLOGY   AND    DISEASE  381 

9.  Phthisis. 

10.  Diphtheria. 

11.  Hydropliobia. 

12.  Erysipelas  and  puerperal  fever. 

13.  Insanity. 

14.  Eheumatism. 

1.  Surgical  Fever  after  operations. — Dr.  Richardson  surgicai 
shows  -^  that  there  are  differences  in  the  mortality  of  ^  ^^'^'  ^" 
certain  diseases  which  are  attended  by  fever  or  increment 
of  animal  heat  during  the  several  seasons  of  the  year. 
He  found,  from  an  analysis  of  139,318  deaths  from  all 
diseases,  during  the  years  between  1838  and  1853,  that 
the  mortality  from  three  of  the  diseases  of  this  class, 
held  the  following  proportions  : — 


shock. 


First 
Quarter. 
Jan.  Feb. 

March. 

Second 

Quarter. 

April,  May, 

June. 

Third 

Quarter. 

Julj',  Aug. 

Sept. 

Fourth 

Quarter. 

Oct.  Nov. 

Dec. 

Scarlet  Fever  . 

20-809 

18-978 

26-234 

33-976 

Erysipelas 

25-144 

23-444 

22-337 

29-174 

Carbuncle 

29-771 

19-685 

24-409 

29-133 

He  points  out  that  the  last  quarter  is  the  central 
quarter  of  the  year  in  which  these  diseases  are  most  fatal, 
and  that  December  is  the  centre  of  a  period  of  seven 
months  which  commences  in  September,  during  which 
there  is  occurring  in  the  animal  organism  a  marked 
modification  in  the  nutrition,  as  compared  with  the  five 
remaining  months  from  April  to  August. 

Admitting  that  whenever  there  is  any  considerable 
increase  of  the  animal  temperature,  there  is  danger,  unless 
there  be  established  a  compensation  by  radiation  and 
specially  by  evaporation  of  water  from  the  body,  we  find 
that  the  fourth  quarter  of  the  year  is  more  distinguished 
than  the  other  quarters  for  those  meteorological  conditions 

1  "On  Meteorological  Eeadings  in  relation  to  Surgical   Practice." — 
Medical  Times  and  Gazette,  January  29  and  February  5,  1870. 


382       METEOROLOGICAL    CONDITIONS   WHICH    FAVOUE 

which  are  most  unfavourable  to  equalization  of  heat  by 
evaporation  and  radiation,  namely,  low  barometric  pressure, 
excess  of  humidity  of  air,  and  a  temperature  low,  but  not 
low  enough  to  compensate  for  increase  of  heat  by  arrest 
of  oxidation  or  by  abstraction  of  heat. 

Dr.  Eichardson  has  accordingly  drawn  up  certain  rules 
for  the  guidance  of  surgeons  in  the  performance  of  opera- 
tions which  will  admit  of  delay,  until  natural  conditions 
arise  favourable  to  operative  work,  whereby  surgical  fever, 
which  often  creates  such  fatality,  may  be  prevented. 

Tlie  time  is  favourcible  for  o;perations — 

(ft)  Wlien  the  barometer  is  steadily  rising. 

(&)  When  the  barometer  is  steadily  high. 

(c)  When  the  wet  bulb  thermometer  shows  a  reading 
of  five  degrees  lower  than  the  dry  bulb. 

(cl)  When,  with  a  high  barometer,  and  a  difference  of 
five  degrees  in  the  two  thermometers,  there  is 
a  mean  temperature  at  or  above  55°  F. 

(e)  Wlien  the  wind  is  west  or  north-west. 

TJie  time  is  unfavourable  for  operations — 

(a)  When  the  barometer  is  steadily  falling. 

(&)  Wlien  the  barometer  is  steadily  low. 

(c)  When  the  wet  bulb  thermometer  approaches  the 

dry  bulb  within  two  or  three  degrees. 
{cT)  Wlien,   with   a    low   barometrical   pressure    and 

approach    to    unity    of   reading    of    the    two 

thermometers,   there   is    a   mean    temperature 

above  45°  and  under  55°  E. 
(e)  "\'\^ien  the  wind  is  south  or  south-west. 

Dr.  A  Hewsoii  has  published  ^  the  results  of  the 
observations  made  in  the  Pennsylvanian  Hospital  by  the 
surgeons,  on  the  relation  between  certain  meteorological 

'  Pennsylvanian  Hospital  RcTports,  voL  ii.  1869. 


OR   RETAED    CERTAIN    DISEASES 


383 


conditions  and  the  mortality  after  surgical  operations. 
They  agree  in  the  main  with  the  conclusions  of  Dr. 
Richardson,  and  elicit  the  additional  fact  that  death  from 
surgical  "  shock "  is  associated  with  a  high  barometrical 
pressure  and  a  dry  air,  conditions  opposite  to  those 
accompanying  fatal  pyaemia.  Dr.  Hewson  writes,  "  We 
obtained  a  mortality,  when  the  operation  was  performed 
with  the  barometer  ascending,  of  10  "7  per  cent,  of  20 '6 
per  cent  with  it  stationary,  and  28*4  per  cent  with  it 
descending." 

French  surgeons  seem  disinclined  to  operate  during 
the  hot  and  sultry  days  of  summer,  fearing  secondary 
hsemorrhage  and  septicaemia.  Eoux,  who  operated  on  a 
large  number  of  cataracts,  reserved  the  operations  until 
spring. 

2.  Small2wx  has  been  found  by  Dr.  Ballard^  in  London,  smaiipox. 
and  by  Dr.  Wistrand  in  Sweden  (in  which  country  there 
is  a  registration  of  disease),  to  prevail  more  from  November 
to  May  than  from  May  to  November.  The  former 
physician  noticed  that  it  has  assumed  an  epidemic  form 
soon  after  the  mean  temperature  of  the  air  has  persistently 
fallen  below  50°  for  the  winter  season,  and  has  begun  to 
decline  in  May,  when  the  mean  temperature  of  the  air  be- 
gins to  rise  above  this  line,  and  gives  place  to  higher 
temperatures. 

The    curve  for   smallpox  in  London  for  a  period  of 


Smallpox — -for  all  Ages  and  both  Sexes. 


+50  p.  ct, 


lean  Line, 


^  Medical  Times  and  Gazette,  March  11  and  13,  1871. 


384       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 

thirty  years  (1845  to  1874),  represented  in  Mr.  Alexander 
Buchan's  and  Dr,  A.  Mitchell's  interesting  research  on 
The  Influence  of  Weather  on  Mortality  from  Different 
Diseases  and  at  Different  Ages,  endorses  these  views. 

The  dotted  line  represents  the  mortality  from  which 
that  of  the  abnormally  high  epidemic  of  1870-72  has 
been  withdrawn.  This  abstraction  has  simply  reduced 
the  sensitiveness  of  the  curve.  The  straight  black  line 
in  this  and  in  the  following  figures  containing  curves, 
indicates  the  mean  weekly  death-rate  on  an  average  of 
52  weeks.  The  curve,  as  it  rises  above  and  falls  below 
the  straight  black  line,  represents  the  average  death-rate 
of  each  week,  calculated  in  percentages  of  the  mean 
weekly  death-rate  for  the  whole  year. 

Dr.  Moore  has  confirmed  these  observations  in  Dublin, 
where  a  well-marked  tendency  to  an  epidemic  was  noticed 
in  March  1871  ;  but  the  disease  appeared  to  be  kept  in 
check  by  the  increasing  temperature,  notwithstanding  the 
importation  from  England  of  many  cases,  until,  with  the 
advancing  autumn  it  blazed  into  an  epidemic.  He  has 
also  noticed^  that  abundant  rainfalls  seemed  to  be 
followed  by  remissions  in  the  severity  of  the  epidemic, 
and  that  the  acme  of  the  epidemic  closely  followed  a 
period  of  comparatively  dry  weather  and  lower  humidity. 

3.  Measles. — Sydenham,  in  his  medical  observations, 
states  that  cases  of  measles  are  generally  most  numerous 
towards  the  end  of  March,  and  that  they  then  gradually 
decline  in  number  and  disappear  by  midsummer.  The 
observations  of  Dr.  Eansome  and  Mr.  Gr.  V.  Vernon  would 
indicate  roughly  that  measles  increases  with  a  fall  and 
diminishes  with  a  rise  of  temperature  ;^  that  barometric 
pressure  fluctuates  more  when  it  is  prevalent  than  when 

1  Manual  of  Puhlic  Health  for  Ireland. 

2  "On  the  Influence  of  Atmospheric  Changes  upon  Disease." — Proc. 
Lit.  Phil.  Soc,  Manchester,  vol.  i.  Series  3,  1859  to  1860. 


OE    EETARD    CEETAIN    DISEASES 


385 


it  is  not  rife ;  and  that  the  period  of  its  recurrence  is 
about  every  five  or  six  years.^ 

This  disease,  which  prevails  especially  during  the 
spring  and  summer  quarters  of  the  year,  would  seem, 
according  to  the  observations  of  Drs.  Moore,^  Ballard,^ 
and  others,  to  be  unfavourably  influenced  by  a  temperature 
of  the  air  above  60°  in  summer,  and  to  be  checked  by  a 
fall  of  temperature  during  winter  below  42°. 

Its  mortality  is  governed  by  other  influences  than 
those  of  a  meteorological  nature.  Cceteris  paribus, 
measles  would  seem  to  be  more  destructive  amongst  those 
who  live  in  total  disregard  of  all  hygienic  rules  than 
amongst  those  who  obey  the  laws  of  health,  and  to  be 
more  fatal  to  native  tribes  amongst  whom  the  disease 
has  been  previously  unknown.  The  severe  epidemic  in 
the  Fiji  Islands,  when  the  disease  was  introduced  by 
Europeans,  affords  a  fresh  proof  of  the  truth  of  this  last- 
mentioned  statement. 

The  measles  curve,  representing  the  fatality  in 
London  from  this  disease,  is  remarkable,  according 
to  Mr.  Buchan  and  Dr.  A.  Mitchell,  in  showing  a 
double  maximum  and  minimum  during  the  year,  a 
rapid   fluctuation   taking    place   from    Christmas   to   the 


Measles — -for  all  Ages  and  hoth  Sexes. 


Jan.     Feb. 
0  p.  ct.    n  I   I      111 


an  Line. 


March     April 
1  I  I  I      III 


0  p.  ct.    LI 


Fig.  4-2 


^  "Epidemic  Cj'cles." — Brit.  Med.  Journal,  September  1,  1877. 
^  Op.  cit. 

^  Eleventh  Eeport  of  the  Medical  Officer  of  the  Privy  Council,  1S6S, 
No.  3,  pp.  54-62. 

2   C 


386       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 


Whooping- 
Cough. 


middle  of  February,  when  the  weekly  deaths  fall  frora 
42  to  21. 

4.  WJioojnng -  Cough. — Extreraes  of  heat  and  cold 
appear  to  affect  not  only  the  prevalence  of  this  disease, 
but  much  more  so  its  mortality.  It  generally  seems  to 
progress  hand  in  hand  with  measles,  increasing  viith.  a 
falling  and  diminishing  with  a  rising  temperature. 
During  the  hot  weather  of  summer  it  is  rarely  heard 
of;  and  during  the  period  when  the  cold,  dry,  east 
winds  blow  in  spring,  it  is  generally  most  fatal  amongst 
the  insufficiently  clothed  and  ill-fed.  We  usually  regard 
it  as  a  winter  and  early  spring  disease. 

Dr.  Moore  thinks  that  intense  cold  checks  the  disease, 
whilst  moderate  cold  favours  its  spread. 

The  London  curve  for  thirty  years  agrees  pretty 
closely  with  these  views. 


Whooping-Cough — for  all  Ages  and  loth  Sexes. 
London. 

Jan.       Feb.    March     April     May     June     July       Aug.     Sept.      Oct.       Nov.      Dec. 


+  50  p.  ct. 


-40  p.  ct 


Fig.  43. 


The  investigation  made  by  Mr.  A.  Buchan  and  Dr.  A. 
Mitchell  into  the  mortality  of  Xew  York,^  conducted  on 

^  "  The  Influence  of  'Weather  on  Mortality  of  Kew  York  from  different 
diseases  and  at  different  ages." — -Journal  Scottish  Meteorological  Society, 
Xew  Series,  vol.  v.,  Xos.  xlix-lxiii.,  p.  171,  1880. 


OR    EETARD    CERTAIN    DISEASES 


187 


the  same  lines  as  that  respecting  London,  shows  that  the 
chief  maximum  of  the  curve  of  New  York  is  almost 
coincident  with  the  minimum  of  London. 

5.  Scarlet  Fever. — Sydenham  considered  that  this  disease  seariet 
appears  most  frequently  towards  the  end  of  summer. 


Fever. 


1 

ft 

> 
■o 

c 
g  g 

1 

o 
> 

F. 

u. 

F. 

u. 

Temperature. 

Humidity. 

Pressure. 

Authority. 

Moderately  low. 

Above  the  aver- 
age. 

Excessive. 

Sudden  fluc- 
tuatifins. 

Diminished 
pressure. 

Dr.  Ransome. 

Between  56° 
and  60°. 

Fall  of  mean 
temperature 
below  53° 
tends  to  arrest 
disease. 

Not  above  S6, 
or  much  less 
tlian  74. 

Dr.  Ballard. 

F. 

u. 

A  temperature 
higher  than 
44-6. 

A  temperature 
below  44'0. 

If  humidity  of 
air  is  less 
tlian  usual. 

Dr.  Tripe. 

F. 

u. 

When  it  rises 
much  above 
50°. 

A  fall  of  mean 
temperature 
below  50°  in 
autumn. 

Dr.  Moore. 

F. 

Mortality 

greater  in  dry                               „„  ^ „*  «■ 

than  wet                                          I^^.  Longstaff. 
season. 

The  Eegistrar-General  of  England  has  noted  a 
tendency  in  the  mortality  from  this  disease  to  increase  in 
London  during  the  last  six  months  of  the  year,  attaining 
a  maximum  in  December.  Dr.  Moore  has  observed  it 
always  to  be  most  prevalent  and  fatal  in  Dublin  during 
the  last  quarter  of  the  year.  Dr.  Wistrand  considers 
that  this  disease  is  most  abundant  in  Sweden  in  Novem- 
ber, and  least  so  in  August. 

The  habits  of  the  people  have  much  to  do,  doubtless, 


388       METEOEOLOGICAL    CONDITIONS    WHICH    FAYOUK 


.  witli  tlie  particular  time  of  the  year  when  the  maximum 
of  the  disease  appears.  My  own  experience  teaches  me  that 
it  increases  with  a  rising  temperature,  spreading  like  wild- 
fire in  very  hot  weather  in  agricultural  villages,  during  the 
times  when  cliildren  congregate  together,  as,  for  example, 
during  hay-making,  pea-picking,  gleaning,  hop-picking,  and 
school  fetes ;  and  that  this  highly  infectious  disease  spreads 
in  towns  and  cities  in  very  cold  weather  amongst  the  poor, 
who  with  their  scanty  supplies  of  fuel,  huddle  together  for 
mutual  warmth,  diligently  closing  every  chink  whereby  fresh 
air  might  possibly  enter  their  overcrowded  dwellings. 

Scarlatina — for  all  Ages  and  hotJi  Sexes. 

LONDOX. 
Jan.      Fel).   March    April       May     June      July      Aug.    Sept. 
+70  p.  ct.   pi  I  '      Ml      MM      Ml      III      I  I  I  I      1  I  I      III      II  I  I 


Mean  Line. 


■50p.  ct.  U  I  I      Ml      I  II  I      Ml       111      II  1  I      III      ill      Mil      III      III      ill 

The  curve  of  ]^ew  York  may  be  roughly  described  as 
the  opposite  of  that  of  London  : — 


New  York. 


+40  p.  ct. 
Mean  Line, 


■  60  p.  ct. 


-1 1 1 

jj^ 

II 1 1 

>W- 

■^sLL 

1 II 1 

i  1  1 

1  1   1 

MM 

1 11 

1 1 1 

mm: 

- 

^-^^ 

- 

N 

^ 

^ 

— 

li  i  1 

1  i  1 

MM 

1  1  1 

1 1 1 

1  n  i 

11       Mi 

•^rrr 

1 1 1 

,  1  i 

M  1  il 

Fig 

.  44. 

The  thirty  years'  curve  for  London  would,  according 
to  Mr.  A.  Buchan  and  Dr.  A.  Mitchell,  show  the 
maximum  death-rate  to  occur  from  the  beginnino-  of 
October  to  the  end  of  November  (when  the  mean  tem- 
perature of  the  air  of  London  is  48-2,  and  its  relative 
humidity  is  85),  and  the  minimimi  to  be  in  March,  April, 


OR    RETARD    CERTAIN    DISEASES 


389 


and  May  (during  which  months  tlie  mean  tempera- 
ture of  the  air  of  London  is  4 7 '3,  and  its  relative 
humidity  is  77). 

The  curves  of  whooping-cough  and  scarlet  fever  form 
striking  contrasts  in  the  case  of  London,  the  maximum 
for  whooping-cough  and  the  minimum  for  scarlet  fever 
both  occurring  in  spring ;  whilst  whooping-cough  reaches 
its  minimum  in  autumn,  when  scarlet  fever  is  at  its 
maximum.  This  conspicuous  difference  does  not,  however, 
obtain  in  the  case  of  K'ew  York.  As  to  the  cycle  of 
scarlet  fever,  Dr.  Eansome  has  noted  ^  that  a  small  wave 
has  appeared  about  every  five  years,  and  a  great  wave 
every  fifteen  or  twenty  years. 

(  Typhus. 
6.  Fever. —  <  Enteric. 

(  Intermittent  and  continued. 
Typlius,  according  to  most  observers,  is  only  indirectly  TypJms 
influenced  in  its  prevalence  Ijy  temperature.      '^Vhen  the 
weather  is  very  cold  cases  are  generally  more  numerous, 

Typhus — for  all  Ages  and  both  Sexes. 

{Bloxam's  Method,  f 
Jan.      Feb.     Marcli    April      May        June      July     Aug.       Sept. 

+40  p.  ct.  n  I  1  I  1  I  I 


Mean  Line. 


-  40  p.  ct. 


^  Op.  cit. 

^  This  irethod  of  dealing  with  the  percentages  in  laying  down  the 
curves  is  convenient  in  arriving  at  an  approximately  true  average  when  a 
small  number  of  years  are  available,  as  in  the  case  of  typhus  and  typhoid 
figures  (for  which  diseases  figures  extending  over  six  years  only  are  obtain- 
able), or  when  few  deaths  occur  from  any  particular  disease,  such  as  gout 
or  ague.  The  method  consists  in  assuming  the  average,  for  instance,  of 
the  second  week  of  January,  to  be  not  the  actual  average  of  that  week,  but 
the  average  of  the  first,  second,  and  third  weeks  ;  the  average  of  the  third 
week  is  assumed  to  be  the  average  of  the  second,  third  and  fourth  weeks, 
and  so  on. 


390       METEOEOLOGICAL    CONDITIONS    WHICH    FAVOUR 

because  the  overcrowding  and  the  defective  ventilation  of 
the  dwellings  of  the  poor  is  worse  than  usual.  The  height 
of  an  epidemic  has  occurred  in  some  instances  during  hot 
weather  (as,  for  example,  in  Glasgow  during  July  1847). 

Mr.  Buchan  and  Dr.  A.  Mitchell  remark  respecting 
the  London  curve,  "  It  is  probable  that  this  curve  has 
two  maxima,  the  larger  in  the  early  months  of  the  year, 
and  the  smaller  in  the  height  of  summer." 

Enteric. — Autumn  is  generally  considered  the  season 
par  excellence  for  the  development  of  this  disease,  hence  it 
has  been  called  in  America  "  autumnal  or  fall  fever."  It 
would  be  more  correct  to  call  it  a  late  autumn  or  winter- 
autumn  fever,  and  diarrhoea  a  summer-autumn  complaint. 
It  has  been  noticed  to  be  more  prevalent  after  dry  and 
hot  summers  than  after  those  which  are  cool  and  wet. 
"Warm,  damp  weather,  in  autumn  and  winter,  when  there 
is  much  decomposition  of  vegetable  matters,  is  favourable 
to  an  outbreak.  Heavy  rains,  by  cleansing  the  air  and 
the  drains,  is  unfavourable  to  its  appearance,  except  when 
filth  is  washed  by  these  downfalls  into  the  wells. 

The  London  curve  for  typhoid  fever  resembles  that 


Typhoid  Fever — -for  all  Ages  and  hoth  Sexes. 


Jan. 

+40  p.  ct.  ri  I  I 


Mean  Line. 


Feb. 
I    I  I 


{Bloxam's  Method. ) 
March    April      May       June      July     Aug.       Sept. 


Oct. 
I 


■  40  p.  ct. 


for  scarlet  fever  as  to  the  period  of  its  maximum  death- 
rate,  but  the  minima  of  these  two  diseases  widely  differ 
in  character  from  one  another. 

The  curve  of  ISTew  York  closely  resembles  that  of  London, 
but  rises  two  months  earlier  to  its  absolute  maximum. 


OE    RETARD    CERTAIN    DISEASES  391 

Temperature— Degrees  Fahr. 

July         Aug.  Sept.  Oct.  Nov. 

1-8  8-7  10-7         12-9 


New  York 

75-4 

73-6 

64-9 

54-2 

41-3 

London  (Greenwich) 

63-8 

63-0 

59-2 

51-9 

42-6 

•8  3-8  7-3         9-3 

When  the  fall  of  temperature  from  one  month  to 
another  is  about  9  degrees  in  both  cities,  then  we  have 
the  absolute  maxima  of  "  Fall  Fever." 

Intermittent  Fever = Ague. — The  popular  idea  in  aguish  Ague. 
districts  that   outbursts  of  this  disease   generally  occur 
when  sudden  changes  of  weather,  from  hot  to  cold  or  the 
reverse,  take  place,  and  especially  during  the  prevalence 
of  a  dry  east  wind  with  a  scorching  hot  sun,  is  interpreted 
by  the  knowledge  that  we  at  present  possess,  as  to  the 
tendency  of  such  meteorological  influences,  to  conduce  to  the 
congestion  of  the  liver,  the  spleen,  and  other  internal  organs. 
(  Diarrhcea. 
7.    <  Dysentery. 
(  Cholera. 
Diarrhcea} — Dr  Eansome  writes  : — "  A  mean  tempera-  Diarrhaa. 
ture  above  60  predisposes  to  diarrhcea  when  con- 
tinuous, causing  a  rapid  increase  in  the  number  of 
cases.     A  temperature  below  60  appears  to  be  un- 
favourable to  its  progress." 
Dr.  Moffat  has  expressed  the  opinion  that,  as  regards 
simple  diarrhoea,  there  is  a  decrease  in  the  pressure  of  the 

^  Great  efforts  have  of  late  years  been  made  to  ascertain  the  mode  of 
causation  of  the  autumnal  form  of  this  disease,  especially  in  children, 
amongst  whom  it  produces  such  a  large  mortality,  and  much  interest  has 
been  excited  on  this  subject  in  Leicester,  which  seems  to  suffer  in  propor- 
tion to  its  population  more  than  other  towns  in  this  country.  Many 
different  views  prevail  in  the  profession  as  to  its  origin.  One  of  the  most 
interesting  is  that  propounded  by  Dr.  John  Shea  in  his  Annual  Report  for 
Reading  for  1880.  He  holds  "that,  when  a  hot  and  comparatively  dry 
summer  month  follows  a  decidedly  wet  month,  diarrhcea  prevails,  due  to 
soil  (telluric)  and  other  exhalations,  and  that  under  such  conditions  these 
exhalations  affect  human  beings,  children  chiefly,  possibly  by  inducing 


392       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 

air  and  an  increase  in  the  force  of  the  wind  on  the  days 
on  which  diarrhoea  occurs,  and  to  a  less  extent  on  the 
days  after  its  occurrence. 

fermentive  changes  in  the  food  and  milk  used  by  them,  stored,  as  sucli 
foods  and  milk  often  are,  in  iinveutilated  cupboards  and  exposed  to  foul 
eflluvia."  In  both  1875  and  1880,  when  there  was  much  mortality  from 
autumnal  diarrhoea  amongst  children  in  and  around  Eeading,  which  could 
not  be  ascribed  to  the  increased  vegetable  matter  in  and  temperature  of 
the  Reading  water  supply,  since  it  occurred  partly  in  the  rural  districts 
outside  its  distribution,  and  which  could  not  be  due  to  hand  feeding,  which 
goes  on  much  the  same  one  year  as  another,  there  occurred  the  sequence 
above  described.  Dr.  Shea  adds,  "  The  natural  tendency  that  is  created  in 
hot  weather  and  hot  climates  to  throw  an  extra  stress  of  elimination  of 
bile  on  to  the  liver,  and  so  induce  bilious  diarrhoea,  must  not  be  for- 
gotten." Dr.  V.  C.  Vaughan,  Professor  of  Physiological  Chemistry 
to  the  University  of  Michigan,  seems  disposed  to  connect  infantile 
diarrhoea  with  the  production,  by  the  growth  of  some  micro-organism, 
of  a  poisonous  alkaloid  or  ptomaine  named  tyrotoxicon,  along  the 
seam  of  the  milk-pail,  or  in  the  rubber  nipple,  tube  or  nursing  bottle. 
Drs.  Guy  and  Harley  say  in  their  work  on  medicine  :  "The  functions  of 
the  liver  and  lungs  are,  to  a  considerable  extent,  vicarious.  The  digestion 
and  assimilation  of  animal  diet  is  attended  by  the  separation  of  a  large 
quantity  of  hydrocarbon  from  the  blood.  If  the  respiratory  function  be 
sufficiently  active,  this  is  consumed  in  the  lungs  and  excreted  as  carbonic 
acid  and  water  ;  but  if,  as  in  tropical  climates,  or  in  very  hot  weather,  the 
respiratory  function  be  insufficient,  the  hydrocarbon  is  separated  hy  the 
liver  in  the  form  of  fatty  acids  of  the  bile.  Now,  in  very  hot  weather  the 
air  per  cubic  foot  contains  necessarily  less  oxygen  than  at  a  lower  tempera- 
ture, hence  for  each  cubic  foot  breathed  less  carbon  is  burnt  off  from  the 
lungs  in  hot  weather  than  in  a  cooler  atmosphere.  Again,  if  with  heat, 
the  air  is  charged  with  moisture  and  is  "steamy,"  the  exhalation  of 
watery  vapour  from  both  the  lungs  and  skin  is  checked  and  thrown  on 
to  the  kidneys  and  bowels.  Both  influences,  excessive  heat  and  moisture, 
therefore,  favour  diarrhoea,  independently  of  other  causes." 

There  is  a  very  strong  popular  belief  in  a  connection  between  a  state  of 
weather  termed  ' '  thunder  weather, "  which  is  most  common  in  autumn,  and 
the  presence  of  diarrhoea.  The  air  being  humid  as  well  as  hot,  drains  and 
cesspools  unpleasantly  obtrude  themselves  on  the  attention,  because  the 
moisture  acts  as  a  medium  of  convej'ance  to  the  nerves  of  smell  of  the 
sewage  emanations  that  are  raised  by  the  heat.  Such  weather  is  not  only 
sultry  and  hot,  but  the  clouds  are  at  the  same  time  laden  with  electricitj'. 
Absence  of  sunlight  anol  the  presence  of  haze  generally  combine  to  form 
the  kind  of  weather  thus  christened.  The  employment  of  fruit  and  vege- 
tables, even  if  fresh,  during  the  prevalence  of  such  weather  is  likely  to 


OR   RETARD    CERTAIN    DISEASES  393 

The  mortality  from  diarrhoea  in  New  York  is  greater 
than  in  London,  doubtless  in  consequence  of  its  greater 
summer  heat.  The  commencement  of  its  increase  is  two 
months  earlier  in  ISTew  York,  due  to  the  increased  tempera- 
ture of  summer  beginning  sooner  than  in  London.      Of 

induce  this  complaint,  although  such  a  result  does  not  usually  follow  a 
sudden  invasion  of  a  high  temperature  during  other  seasons  of  the  }'ear. 

It  is  probable  that  such  evidence  will  soon  be  forthcoming  for  the  use 
of  the  profession  as  will  conduce  to  a  settlement  of  this  question  which 
has  been  so  long  suh  jiidice.  Dr.  Ballard,  in  the  inquiry  with  which  he 
has  been  entnisted  into  the  causes  of  autumnal  diarrhoea,  is  engaged  in 
investigating  the  temperature  of  the  earth  at  1  foot  and  at  4  feet  in  depth, 
and  has,  I  learn,  ascertained  some  curious  facts  with  reference  to  the 
prevalence  of  the  disease  being  coincident  with  the  periods  between  the 
crossing  of  the  readings  of  these  earth  thermometers,  which  I  am  not 
authorized  to  disclose,  but  which  he  will  doubtless  in  due  time  publish. 
The  fact,  pointed  out  by  Drs.  Lewis  and  Cunningham  ("Cholera  in 
relation  to  certain  Physical  Phenomena ")  with  reference  to  cholera  in 
India,  that  the  great  maximum  of  prevalence  in  April  and  the  mini- 
mum in  November  both  occur  when  the  soil  temperature  at  6  feet 
from  the  surface  is  between  78°  and  79°  P.,  would  seem  to  have  a  bearing 
on  this  question.  Dr.  Ballard  will  not,  I  trust,  fall  back  upon  the  con- 
clusion that  this  disease  is  attributable  to  earth  emanations,  without  a 
rigorous  exclusion  of  the  evidence  showing  the  influence  of  temperature 
and  alternations  of  temperature  in  its  production  under  ceitain  conditions 
of  the  human  body  and  of  climate.  The  compensatory  interchanges 
between  the  skin  and  the  mucous  membrane  of  the  intestinal  tract  are 
well  known,  but  perhaps  hardly  sufBciently  borne  in  mind.  Sudden  heat 
or  sudden  cold  will  p)roduce  diarrhoea,  and  young  children,  amongst  whom 
the  mortality  is  greatest,  are  more  influenced  by  such  changes  and  are  less 
able  to  withstand  the  impact  of  a  severe  drain  on  their  resources  of  strength 
than  adults  and  middle-aged  individuals.  "When  the  skin  is  acting  freely 
during  the  hot  summer  months,  when,  as  the  public  say,  "  the  pores  are 
open,"  any  sudden  chill  or  cessation  of  perspiration  may,  as  every 
medical  man  knows,  produce  a  determination  of  blood  to  the  biliary  organs 
(exciting  an  increased  flow  of  bile)  and  to  the  intestinal  tract,  probably  at 
the  time  irritated  by  decomposing  milky  food,  or  decomposing  and  half- 
digested  fruit,  such  as  plums,  etc.,  and  a  flux  results.  On  the  other  hand, 
a  sudden  check  to  the  action  of  the  skin  by  cold,  unless  followed  by  the 
glow  of  a  reaction,  may  induce  an  attack  of  diarrhoea,  and  this  flow  is  often 
welcomed  as  an  easy  way  of  getting  rid  of  a  catarrh.  I  have  never,  since 
the  publication  of  Dr.  C.  F.  Oldham's  book,  entitled  What  is  Malaria.  ? 
referred  to  on  p.  234,  been  alloiccd  by  facts,  that  have  every  now  and 
then  come  to  my  knowledge,  to  forget  it. 


394       METEOROLOGICAL    CONDITIOXS    WHICH    FAVOUR 
Dijsentery,  Diarrhcea,  and  CJiolera—for  all  Ages  and  both  Sexes. 

Jan.    Feb.      March    April     May      June      July    Aug.      Sept.      Oct.      Nov.      Dec. 
LM  I      I  I  I  I  I  I  I  I      III      III      I  I  I  I      III      111      1111      [  ]  I      1,1      1,1 


+500  p.  ct 


+  400 


+300 


+  200 


+  100 


Mean  Line. 
Dysentery. 


DiaiThcea. 
Cholera  (2). 
Cholera  (1). 
- 100  p.  ct. 


Fig  47. 


all  the  deaths  in  New  York  from  diarrhoeal  affections,  69 
per  cent  occur  amongst  infants  under  one  year,  18  per 
cent  between  1  and  2  years,  and  '06  per  cent  from  10  to 
20    years.     How   strongly   does   this   enormous   fatality 


OR    RETARD    CERTAIN    DISEASES  395 

amongst  infants  point  to  the  want  of  good  milk,  which 
should  be  the  sole  food  of  infancy. 

Dysentery. — "Dysentery,"  writes  Dr.  Eansome,-^  "seems Dysentery. 
to  be  increased  by  a  high  mean  temperature  and  diminished 
by  a  low  mean  temperature,  but  to  be  influenced  by  varia- 
tions of  temperature  to  a  less  extent  than  diarrhoea. 
High  readings  of  the  barometer  are  nearly  always  accom- 
panied by  a  diminished  prevalence  of  dysentery." 

Cholera. — The  history  of  past  epidemics  has  generally  choiera. 
taught  us,  with  but  two  or  three  exceptions,  that  the 
mortality  from  this  disease  usually  increases  until 
September,  when  it  reaches  its  maximum,  after  which 
it  begins  to  decline.  A  sudden  diminution  in  the  extent 
of  its  ravages  is  often  ushered  in  by  some  great  natural 
cleansing  process,  such  as  a  storm  of  wind,  or  heavy 
downfall  of  rain,  or  sudden  descent  of  temperature 
diminishing  decomposition  of  organic  matters. 

The  London  curves  for  these  diseases  show  the  close 
relationship  that  the  progress  of  mortality  from  them 
bears  to  temperature.^  The  speed  at  which  they  suddenly 
increase  during  the  hottest  weeks  of  the  year,  and  rapidly 
decline  on  the  fall  of  the  thermometer,  is  very  striking. 

The  dotted  line.  Cholera,  No.  1,  indicates  the  fatality 
from  Asiatic  Cholera.  The  line  not  dotted,  Cholera,  No. 
2,  represents  simple  or  English  cholera. 

The  maximum  and  minunum  of  diarrhcea  is  seen  to 
be  a  month  earlier  than  the  maximum  and  minimum  of 
dysentery, 

Mr.  Buchan  and  Dr.  A.  Mitchell  point  out  that  the 
four  curves  seem  to  group  themselves  in  pairs — diarrhoea 
and  English  cholera  on  the  one  side,  and  dysentery  and 

^  0}}  cit. 

^  It  is  stated  in  the  Annuaire  dc  V Ohservatoire  de  Montsouris  for  1886 
that,  during  the  last  epidemic  of  cholera  in  Paris  in  1884,  the  increase  in 
the  number  of  deaths  was  not  accompanied  by  an  increase  of  the  tempera- 
ture ;  but  that  the  micro-organisms  in  the  air  of  Paris  and  its  neighbourhood 


396       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 


Asiatic  cholera  wliich  pass  through  their  annual  phases 
a  month  later,  on  the  other. 

8.  Bronchitis,  Pneumonia,  and  Asthma. — These  diseases 
are  greatly  influenced  by  mean  temperature.  They  increase 
in  prevalence  as  the  temperature  falls,  and  diminish  as  it 
rises.      The  London  curves  strikingly  exemplify  this  fact. 

The  percentages  of  the  mean  weekly  death-rate  at 
different  ages  are — 

From  Bronchitis. 


AGES. 
1-5  I  5-20  I  20-40  I  40-60  |  60-80 


Above  80  I  Total. 


38 


61 


17 


34 


6 


From  Pneumonia. 
10     I     13     I      9      I 


100 


100 


Bronchitis  is  thus  seen  to  be  most  fatal  to  children 
under  5  years,  and  to  the  old ;  whilst  pneumonia, 
although  specially  fatal  to  children  below  this  age,  is  of 
rare  occurrence  amongst  the  aged. 

The  principal  maximum  of  pneumonia  in  November- 
December,  is  chiefly  determined  by  the  large  number  of 
deaths  amongst  children  under  five  years,  whilst  the 
secondary  maximum  occurs  in  March.  Dr.  "William 
Squire  does  not  apparently  recognize  the  existence  of 
two   maxima,  but   contends   that   the    annual  maximum 

were  much  more  abundant  than  usual  during  the  days  when  the  deaths 
were  most  numerous. 


Dates. 

Bacteria  pee 

Cub.  Metre. 

Deatlis  from 
Cholera. 

November  1884. 

Montsoiiris  Park. 

Rue  de  Rivoli. 

From    1-  4 

110 

1200 

2 

„       5-  8 

190 

1150 

63 

,,       9-12 

245 

2120 

349 

,,     13-16 

340 

1360 

268 

,,      17-20 

255 

880 

150 

,,     21-24 

185 

1120 

76 

..     25-28 

50 

220 

40 

OR    KETAED    CERTAIN    DISEASES 


397 


Bronchitis,  Pneumonia,  and  Asthma — for  all  Ages  and  both  Sexes. 

Jan.      Feb.     Marcli    April     May       June      July     Aug.      Sejjt.      Oct.     Nov.      Dec. 


+  130  p.  ct. 


+ 1  on  p.  ct. 
Asthma. 


-SOp.  Ct.      LI   I 


of  pneumonia,  unlike   that   of  bronchitis,  is    always   in 
spring. 

It  is  unwise  to  associate  closely  bronchitis  and  pneu- 
monia in  their  causative  relations  with  temperature,  or  by 
so  doing  we  become  oblivious  to  the  fact  to  which  Dr. 
Longstaff  has  directed  attention,^  that,  whereas  1104 
males  die  from  bronchitis  to  every  1000  females,  but 
as  many  as  1460  males  die  from  pneumonia  to  every 
1000  females,  the  cause  of  the  two  diseases  is  somewhat 
different.  The  catarrhal  form  of  pneumonia  should  be 
distinguished  from  its  specific  form.  Dr.  Seibert^  has 
established  a  close  relationship  between  the  prevalence  of 
catarrhal  pneumonia  and  those  meteorological  conditions 
wliich  favour  catarrh,  such  as  a  concurrence  of  any  two 
of  the  following  factors — a  low  and  falling  temperature, 
an  excessive  and  increasing  humidity  and  high  winds. 
The  existence  of  an  infectious  form  of  pneumonia,^  named 
also  "  pneumonic  fever,"  "  sewer  gas  and  pythogenic  pneu- 

^  "  Phthisis,  Bronchitis,  and  Pnenmonia :  Are  they  Epidemic  Diseases  ?" 
— Contribution  to  Epidemiological  Society  of  London. 

2  Berl.  Klin.   JFochenschr.,  18S6,  No.  17. 

3  Vide  "Pythogenic  Pneumonia,"  by  Drs.  Grimshaw  and  Moore,  in 
Dublin  Journal  of  Medical  Science,  May  1875,  and  Dictionary  of  Hygiene, 
p.  452. 


398       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 


Phthisis 
Pulinonalis. 


monia,"  is  now  no  longer  a  matter  of  doubt.  Unlike 
ordinary  pneumonia,  it  is  an  infectious  disease  with  a 
period  of  incubation,  occurring  sometimes  in  an  epidemic 
form,  and  prevalent  in  the  warmer  months  of  the  year. 

9.  Phthisis  Pidmonalis. — This  disease  destroys,  on  an 
average,  148  individuals  in  London  every  week,  and  its 
fatal  assaults  are  directed  against  those  in  the  prime  of 
life,  differing  in  this  respect  entirely  from  bronchitis.  In 
New  York  it  is  the  most  fatal  of  all  diseases,  amounting 
to  ^th  of  the  total  mortality. 

Phthisis — for  all  Ages  and  both  Sexes. 


+30  p.  ct. 
Mean  Line. 

Jan. 
I'  '  1 

Feb. 
1  1  1 

March 
1  1  1  1 

April 
M  1 

May 
1  1  1 

June 
fill 

July 
1  1  1 

Aug. 
1   1   1 

Sept. 
1   1   1  1 

Oct. 
1  1  1 

Kov. 
1  1  1 

Dee. 

1 11  r 

-  30  p.  ct. 

J  1  1 

1  1  i 

1  1   1  1 

1  1  i 

1  1  1 

II  11 

1  1  1 

1  1   1 

II   11 

1  1  1 

i  1  1 

M  1  il 

Diphtheria.  \{)  Di-phthevia. — There  is  a  close  correspondence  be- 
tween the  diphtheria  curves  of  London  and  New  York,  and 
between  both  of  these  curves  and  the  scarlatina  curve  of 
London.  The  influence  of  cold  and  the  season  of  the 
year  on  diphtheria  is  recognized  by  medical  practitioners. 
According  to  my  experience,  which  extends  back  to  1856, 
the  damp,  cold  days  of  November,  and  the  dry,  cold  days 
of  the  early  months  of  the  year,  have  been  most  prolific 
in  cases.  Dr.  Thursfield's  "Table  of  Deaths," ^  from  1870 
to  1877  inclusive,  yields  the  following  averages : — 


Quarter  of  the  Year. 

Deaths. 

Jlean 
Temperature. 

Rainfall  in 
inches. 

First       . 
Second  . 
Third     . 
Fourth   . 

735 

678 
547 
750 

40-5 
52-5 
60-6 

43-7 

5  0 
4-5 
70 
7-5 

Lancet,  August  3,  1878. 


OK    RETARD    CERTAIN    DISEASES 


399 


The  question  which  requires  elucidation  is,  as  to 
what  influence  (if  any)  is  exerted  by  the  amount  of 
moisture  in  the  air  on  the  development  of  the  diphtheritic 
micro-organism.  The  virus  of  this  disease  seems  to  be 
communicated  from  one  to  another,  if  not  by  actual  con- 
tact (as  by  kissing  and  otherwise),  through  the  medium 
of  foul  air,  foul  water,  or  foul  milk. 

11.  Sydroplwlia. — The  hot  "dog  days"  of  summer  Hydro- 
are  generally  considered  to  be  those  during  which  this^^^°^'^" 
disease  is  most  prevalent,  and  this  ancient  belief  is 
justified  to  some  extent  by  facts,  although  we  must 
remember  that  it  shows  itself  to  be  independent  in  its 
spread  of  a  high  temperature,  as  the  following  curve  of 
the  mortality  in  London  during  30  years  proves: — 

Hydrophobia — -fo^'  all  Ages  and  both  Sexes. 


Jan.      Feb.    March    April     May     June       July    Aug.      Sept.      Oct.    Nov.       Dec. 


5  cases 
4     „ 
3     „ 

2      „ 
1      ,, 


11   I  I  I   [   I 


1 1  1 1 


I  BH  I  I  I 


I  i  I 


I  I  1  r 


Fig.  50. 


The  number  of  cases  in  December  is  there  seen  to  be 
as  numerous  as  those  in  August.  More  persons  are 
doubtless  bitten  by  dogs  in  hot  weather,  because  dogs 
are  more  irritable  during  this  season.  We  want  an 
answer  to  the  query  as  to  the  percentage  of  cases  of 
hydrophobia  in  those  who  are  bitten  in  each  month  of 
the  year,  before  we  can  determine  with  certainty  the 
influence  of  meteorological  conditions  on  the  disease. 

12.   Erysipelas  and  Puerperal  Fever. — The   curves  of  Erysipelas. 
mortality  for  30  years  in  London  from  these  two  diseases 
wonderfully  resemble  each  other,  and  are  highly  suggestive 
of  a  more  intimate   relationship  between  them   than  is 
generally  conceded. 


400       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUR 


Erysipelas — for  all  Ages  and  both  Sexes. 

Jan.      Feb.     March    April     May      June      July     Aug.      Sept.      Oct.     Nov.      Dec. 


^^ 


-  40  p.  ct 


Fig.  51. 


Puerperal 
Fever. 


Puerjjeral  Fever  or  Metria — for  all  Ages. 
{Bloxam's  Method. ) 
Jan.      Feb.     March    April     May      June      July     Aug.       Sept.       Oct.      Nov.     Dec. 


+50  p.  ct.  n  I 


-  50  p.  ct.   D  I  i  J  I   I  I      1  I  I  I      111       III      II  I  I      III      111      II  1  I      III      III 


Fig.  52. 


Insanity.  13.  Insanity. — The  London  curves  for  diseases  of  the 

nervous  system  are  interesting.      Tliat  of  insanity  may 
be  taken  as  a  sample  of  the  others. 

Insanity — for  all  Ages  and  both  Sexes. 
(Bloxctm's  Method. ) 
Jan.      Feb.      March    April    May      June       July    Aug.       Sept.      Oct.    Nov. 
+40  p.  ct.  Ul  I 


Mean  Line. 


Dec. 
I  I 


-40p.  ct.  D  I  I      Ml      III 


I      III      II 

Fig.  53. 


This  curve  shows  three  maxima,  tlie  largest  being  in 
December  and  January,  the  next  in  June,  and  the  least 
marked  in  March  and  April. 

The  New  York  curve  for  "All  nervous  diseases" 
exhibits  a  considerable  maximum  in  July — the  hottest 
month  of  the  year — owing  no  doubt  to  fatal  cases  of 
sunstroke. 


OR    RETARD    CERTAIN    DISEASES 


401 


14.    Rheumatism. — Eheumatic    fever    was    said    byRiieum 
Sydenham  to  be  most  common  during  the  autumn.      The  '^"' 
London  curve  does  not  confirm  his  view. 


Rheumatism — for  all  Ages  and  both  Sexes. 


Jan.      Feb. 


+40  p.  ct.   n 


Mean  Line. 


-  40  p.  ct. 


March 
I  I  I  I 


Dec. 


Sub-acute  rheumatic  affections  of  joints  would  seem 
to  be  more  uncomfortable  to  their  possessors  when  the 
barometer  is  low,  and  the  air  is  warm  and  moist,  and 
chronic  cold  rheumatic  affections  of  the  aged,  in  whom 
the  skin  is  inactive,  are  apparently  benefited  by  this 
"  muggy  "  condition  of  the  air.  Both  kinds  of  rheumatic 
joints  are  incommoded  by  a  sudden  diminution  of  pressure 
and  perhaps  by  a  low  atmospheric  pressure  (vide 
page  374). 

The  curve  of  pericarditis  is  very  similar  to  that  ofpericai 
rheumatism,  as  every  medical  man  would  of  course  ^^*'^' 
conjecture.  Dr.  Longstaff  and  Messrs.  Bnchan  and 
Mitchell  all  state  that  the  curve  of  pleurisy  resembles 
more  closely  that  of  rheumatism  than  that  of  the  re- 
spiratory diseases — a  circumstance  which  strengthens  my 
belief  in  the  existence  of  an  etiological  relation  between 
rheumatism  and  pleurisy. 

Before  concluding  this  sketch  of  the  influence  of 
meteorological  conditions  on  mortality,  it  would  be  in- 
structive to  consider  briefly: — (1)  The  influence  of 
weather  on  the  mortality  at  different  ages  ;  and  (2)  The 
influence  of  weather  on  the  mortality  of  the  two  sexes. 

"  The  broad  fact  which  the  following  diagrams  (fig.  5  5  Mortal 
and  fig.  56)  disclose  is,"  as  has  been  stated  by  Mr.  Buchan 

2  D 


at  diffe 
ages. 


402       METEOROLOGICAL    CONDITIONS    WHICH    FAVOUE 

and  Dr.  A,  Mitchell,  "that  the  New  York  curve  receives 
its  leading  characteristics  from  a  great  fatality  there  of 
diseases  which  have  their  maxima  as  causes  of  death  in 
the  hot  months  (diseases  of  the  abdominal  organs),  and 
that  the  London  curve  receives  its  form  from  a  compara- 
tively lower  fatahty  of  such  diseases,  and  a  comparatively 


Mortality  at  different  Ages,  for  loth  Sexes  and  all  Causes. 
London. 

Jan.     Feb.      March    April     May      June      July     Aug.      Sept.      Oct.     Nov.      Dec. 

Ill    iiiiMii    Ml    rii    irii    III    iiiinirrin    iTrriri! 


higher  fatahty  of  the  diseases  wliich  have  their  maxima 
as  causes  of  death  in  the  winter  and  spring  months 
(diseases  of  the  respiratory  organs  and  of  the  nervous 
centres)."  The  deaths  from  respiratory  diseases  during 
the  winter  and  spring  months  in  London  are  shown,  by 
the  maintained  excessive  height  of  the  respiratory  diseases 
curve  at  those  seasons,  to  be  enormous  in  young  children. 
The   major    part   of   this    winter   mortality    arises    from 


OR    RETAED    CERTAIN    DISEASES 


403 


diseases  of  the  respiratory  organs.  This  excess  in  our 
insular  climate  over  that  of  the  much  drier  continental 
climate  of  New  York  must  be  ascribed  to  the  greater 
dampness  associated  with  the  cold,  and  to  the  greater 
vicissitudes  of  weather  which  we  islanders  experience. 
In  December  and  January,  when  the  air  is  most  humid. 


Mortality  at  different  Ages,  for  both  Sexes  and  all  Causes. 
New  Yoek. 

Jan.     Feb.     March     April     May      June      July     Aug.      Sept.     Oct.  Nov.       Dec. 

JJ  I      III      )  I  I  I      111      III      1111      111      111      I  I  I  I      III  111      I  I  I  I 


Fig.  56. 

the  relative  humidity  of  New  York  is  79,  and  of  London 
87.  The  annual  minimum  of  New  York  is  62,  and  of 
London  72.  The  mortality  curve  at  the  opposite  end 
of  life,  in  persons  upwards  of  80,  appears  to  be  a  very 
simple  one,  having  its  maximum  in  cold  and  its  minimum 
in  warm  weather.  The  curve  indicative  of  summer 
mortality  from  diarrhoea  is  seen  to  be  somewhat  affected 
in  adults  in  the  hotter  climate  of  New  York. 


Mortality  of 
each  sex. 


404       METEOEOLOGICAL    CONDITIONS    WHICH    FAVOUR 

The  period  of  the  year  when  females  have  a  higher 
death-rate  than  males  is  when  diseases  of  the  respiratory 
organs  are  most  fatal,  and  the  period  when  females  have 
a  lower  death-rate  than  males  is  when  diseases  of  the 
nervous  system  are  most  fatal. 


Death  of  each  Sex  from  all  Causes — 3iales  being  represented  by 
the  solid  line,  and  Females  by  the  dotted  line. 


Nov.      Dec. 
II      I  I  II 


Fig.  57. 


The  curve  of  the  mortality  of  each  sex  consists  of 
three  distinct  portions,  o}  a?  the  respiratory  disease  mor- 
tality, h  h  the  nervous  disease  mortality,  and  c  the 
intestinal  disease  mortality.  The  respiratory  disease 
mortality  during  the  commencement  of  the  year,  a^,  is 
higher  than  that  of  the  end  of  the  year,  even  after  an 
allowance  is  made  for  the  support  afforded  by  the  two 
maxuna  of  the  nervous  disease  mortality.  Nearly  the 
whole  of  the  intestinal  affection  mortality  is  created  by 
the  death  of  infants  under  one  year.  If  we  could 
diminish  the  mortality  to  any  considerable  extent  from 
these  three  kinds  of  disease,  namely,  the  respiratory, 
the  nervous,  and  the  intestinal,  the  curve  of  mortality 
would  become  very  much  flattened  and  approach  in 
appearance  the  curve  of  old  age.     Here  the  end  gene- 


OR    RETARD    CERTAIN    DISEASES 


405 


rally  comes,  it  would  seem,  from  some  respiratory  affec- 
tion (fig.  58). 

Old  Age — -for  both  Sexes.  om  age. 


f  50  p.  ct. 
lean  Line. 
-50  p.  ct. 

Jan. 

Feb. 
1    1  1 

March 
Mil 

April 
1  1   1 

May 
1   1   1 

June 
1  1  1  1 

July 
1  1  1 

Aug. 
1  1   1 

Sept. 
MM 

Oct. 
1  1  1 

Nov. 
1    1  1 

Dec. 

Mir 

J    1    1 

1   1  1 

1  1  1  1 

1  1   1 

1  1  1 

1  1  11 

1  1  1 

1  1   1 

i   1   M 

1  1  1 

1 1 1 

1  1  i  ll 

Fig.  58. 


No  more  space  can  be  allotted  for  the  consideration 
of  the  relations  of  atmospheric  states  and  conditions  of 
the  air  to  disease,  as  it  is  necessary  to  describe  the  mode 
of  observing  meteorological  variations  according  to  the 
most  recent  and  approved  methods. 


9  T^  9 


PAET    IV 

MODE    OF    OBSERVING    THE    METEOROLOGICAL    STATES    AND 
VARIATIONS    IN    THE    CONDITION    OF    THE    AIR 

In  commencifig  a  series  of  meteorological  observations 
it  is  necessary  to  know  the  height  above  the  sea  of  the 
place  of  observation. 

This  is  readily  found  by  making  a  search  for  the 
nearest  bench  mark  of  the  Ordnance  Survey,  and 
ascertaining  by  a  rough  estimation,  or  by 
the  help  of  a  surveyor  and  his  sj^irit  level, 
the  difference  between  the  level  of  that 
bench  mark  and  the  station  where  our 
Fig.  59.  instruments  are  exposed.  As  the  publi- 
cations of  the  Ordnance  Survey  are  not  readily  accessible, 
it  will  afford  me  much  pleasure  to  give  any  applicant  the 
height  of  any  bench  mark. 

The  hours  of  observation  that  are  best,  if  two  obser- 
vations are  taken  daily,  are  9  a.m.  and  9  p.m. 


CHAPTEE    XXXIII 

1. THE    ATMOSPHERIC    PRESSURE 

There  are  three  principal  classes  of  barometers — the  sarometei* 
syphon,  the  aneroid,  and  the  cistern.  The  wheel  baro- 
meter, so  common  in  the  passages  and  halls  of  houses, 
is  an  example  of  the  first  class,  and  is  useless  for  all 
scientific  purposes.  The  aneroid  is  not  a  thoroughly 
reliable  instrument,  unless  checked  frequently  by  means 
of  a  good  mercurial  barometer.  It  varies  very  much  in 
excellence  according  to  the  skill  and  delicacy  of  work- 
manship bestowed  on  it.  Fortin's  cistern  barometer  is 
the  instrument  for  the  scientific  man.  A  long  strip  of 
white  porcelain,  fixed  to  the  board  at  the  back  of  the 
scale,  facilitates  accuracy  of  reading.  There  are  three 
points  to  be  remembered  in  making  an  observation  with 
one  of  these  instruments,  and  they  should  be  attended  to 
in  the  order  in  which  they  are  mentioned — 

Firstly.  The  temperature  of  the  attached  thermo- 
meter should  be  noted  and  recorded. 

Secondly.  The  screw  at  the  base  of  the  cistern  should 
be  adjusted  until  the  point  of  the  ivory  cone 
visible  within  it  meets  the  reflection  of  the  same 
that  is  seen  on  the  surface  of  the  mercury.  A 
piece  of  looking-glass  placed  at  the  back  of  the 


408 


THE    ATMOSPHEEIC    PRESSURE 


cistern  is   a  great  aid   to  the  observer  in   dull 
weather. 


c 

1 

5 

I 

1^ 

LEVEL   OF 
MERCURY 


Fig.  60. 

a.  Interior  of  cistern. 

b.  Mercury. 

c.  Tube  containing  mercury. 

d.  Ivory  point  fixed  to  top  of  cistern. 


e.  Reflection  of  same,  seen  on  surface  of 

mercury. 
/.  Screw  for  elevating  or   lowering  the 

level  of  the  mercury  in  the  cistern. 


Thirdly.  The  vernier  should  be  adjusted  so  that  its 
lower   horizontal   edge   forms   a  tan- 

o 

mercurial  column,  and  not  an  arc  to 
that  curve. 


There  are  corrections  to  be  considered 
in  making  barometrical  observations,  namely, 
those  for  index  error,  capacity,  and  capil- 
larity, furnished  by  the  certificate  of  verifi- 
cation from  the  Kew  Observatory,  which 
should  accompany  every  good  instrument ; 
the  correction  for  height  above  mean  sea 
level ;  and  the  correction  for  temperature. 

Three  simple  arithmetical  calculations  have  then  to 
be  applied  to  every  reading — 

{a)   Correction  of  Kew  certificate. 

(b)  Eeduction  to  mean  sea-level. 

(c)  Eeduction  to  32°  F. 


FiG.61. 


THE   ATMOSPHERIC    PEESSUKE  409 

Tables  are   published  by  the  help  of  which  both  of  Application 
these   reductions   are   accomplished   easily   and   rapidly.-^  tjo^°"o°" 
For  example  : —  readings. 

Observed  reading  .  .  .  .  .28*900 

Kew  correctiou  .  ,  .  .  .        —  "015 

28-885 
Deduct  temp,  correction  for  50°  F.  (attached  therm.)  at 

28-9  or  about  29  inches    .  .  .  ,        -  -056 


Reading  at  32°  F.         .  .  .  .  .       28*829 

Correction  for  height  (350  ft.),  the  air  being  50°  F.        .        +  -380 


Observed  reading  corrected  and  reduced  to  32°  F.  at 

mean  sea-level      .  .  ,  .  .       29*209 


Adie's  barometers  are  useful  instruments,  in  which 
allowances  are  made  for  the  capillarity  and  capacity 
errors  in  their  construction.  There  are  two  kinds — one 
adapted  for  a  house  or  observatory,  and  the  other  the 
marine  variety,  which  will  work  efficiently  when  exposed 
to  the  motion  of  the  ship. 

In  making  an  observation  with  an  Adie's  barometer, 
it  is  simply  necessary  to  read  the  height  by  the  help 
of  the  vernier,  and  apply  to  the  observed  reading  the 
necessary  corrections  for  height  and  temperature. 

The  exact  height  of  the  column  of  mercury  is  read  Mode  of 
thus :—  '"^^<^'°^- 

In  rig.  61  the  zero  of  the  vernier  is  on  a  level  with 
the  line  indicating  29^,  so  we  record  the  reading  as 
29-50. 

If  the  zero  of  the  vernier  and  the  scale  occupy  such 
relative  positions  as  are  sketched  in  Fig.  62,  we  read 
the  barometer  to  1000th  of  an  inch  in  this  way  : 

^  Mr.  Glaisher's  and  Mr.  Lowe's  tables  are  employed  and  may  be  found 
at  the  end  of  either  of  Mr.  Buchan's  elementary  books  on  meteorology,  or 
may  be  obtained  from  Messrs.  Negretti  and  Zambra,  or  Messrs.  Casella  and 
Co.,  the  meteorological  instrument  makers. 


410 


THE    ATMOSPHERIC    PRESSURE 


1.  We  see  that  the  reading  is  somewhere  between  29 
and  30,  so  we  write  down  29. 
D  2.  We  perceive  that  the  zero  of  the 

vernier  is  on  a  level  with  a  part 
of  the  scale  somewhere  between 
1    and    2    tenths,    counting  up- 
wards, and  that  it  is  more  than 
1^  or   "15,   so   we   write  down 
29-15. 
3.  We  then  glance  down  at  the  sub- 
divisions of  tenths  on  the  scale 
and  on  the  vernier,  in  order  to 
discover    which    subdi"vdsion    of 
the  scale  lies  in  one  and  the  same 
straight  line  with  a  subdivision 
*    on  the  vernier.     In  the  accom- 
panying   example    we    perceive 
that  this  takes  place  at  the  line 
on  the  vernier  just  above  figure 
3,  namely,  at  '034,  which,  when 
added  to  the  scale  reading  29*15, 
equals    29*184,   which   we   call 
the  observed  reading. 
With  a  little  practice  barometer  read- 
ings to  the  1000th  of  an  inch  can  be 
taken  with  the  greatest  ease  and  rapidity. 
'  stfe  o'ftet™S        It  i«  occasionaUy  desirable  to  ascertain 
and  A  B  is  the  sUding  whether  tlic  spacc  above  the  mercurial 

scale  or  vernier.  t  .,.,„.  -n  .  i 

column  IS  devoid  oi  air.  By  gently 
inclining  a  barometer,  so  as  to  allow  the  column  of 
mercury  to  strike  against  the  top  of  the  tube,  a  sharp 
metallic  click  should  be  heard.  If  such  a  sound  is  not 
audible,  air  is  present  where  a  vacuum  should  exist.  If 
the  air  cannot  be  expelled  by  inverting  the  barometer,  it 
should  be  taken  to  an  instrument  maker. 


3 

— 

- 

30 

•5 

- 

— 

- 

-^ 



' — 

- 

% 

— 



29  • 

c 

Fig.  62. 


CHAPTEE    XXXIV 

2. THE  TEMPEEATUEE  OF  THE  AIE 

The  thermometers  required  are  the  folio  wing  : —  Tiiermo- 

1.  The   dry  bulb   thermometer  of   Mason's  hygrometer,™*  "^"^^^ 

described  on  page  424,  furnishes  the  temperature  of 
the  air  in  the  shade. 

2.  A  mercurial  maximum   self -registering   thermometer, 

for  indicating  the  highest  temperature  reached  by 
the  air  in  the  shade.  I  prefer  the  pattern  made  by 
Negretti  and  Zambra,  but  those  of  other  makers  are 
very  good.  The  maximum  temperature  of  the 
twenty -four  hours  generally  occurs  about  3  p.m. 

3.  A  self-registering  minimum  thermometer  for  recording 

the   lowest   temperature  of  the   air   in   the   shade. 
Many  laborious  attempts  have  been  made  to  manu- 
facture if  possible  mercurial  minionuTn  thermometers 
because  : — (a)  in  spirit  minimum  thermometers  there 
is  a  tendency  to  the  evaporation  of  the  spirit,  and  a 
condensation  of  it  at  a  distance  from  the  column,  and 
to  the  breaking  up  of  the  column  into  distinct  por- 
tions ;  (b)  it  is   desirable  to  employ  the  same  fluid 
mercury  for  registering  minimum  temperatures  as  that 
for  recording  maximum  and  other  temperatures. 
Casella's    mercurial    self-registering    minunum    ther- 
mometers are  most  beautiful  instruments,  but  cannot  be 
recommended  for  general  use,  as  they  require  the  most 
delicate   manipulation,  and    they   cannot,  it  appears,  be 


412  THE    TEMPEEATUEE    OF    THE    AIE 

made  so  as  to  stand  wear  and  tear.  I  have  had  one  in  use 
for  many  years,  and  it  has  never  once  been  deranged  in  its 
action,  but  it  was  selected  from  amongst  many.  JSTegretti 
and  Zambra  have  sold  for  years  a  mercurial  minimum 
thermometer  with  a  bulb  of  very  large  dimensions.  This 
firm  has,  I  believe,  unproved  upon  it,  and  patented  another 
provided  with  a  needle.  The  extra-sensitive  self-register- 
ing spirit  minimum  thermometer  of  Casella,  with  a  forked 
bulb,  is  an  excellent  instrument.  If  the  column  of  spirit 
should  happen  to  separate,  it  can  be  reunited  by  taking 
the  thermometer  in  the  hand  farthest  from  the  bulb,  and 
giving  it  one  or  two  sharp  swings.  The  thermometer 
should  then  be  hung  in  a  slanting  position,  so  as  to  allow 
the  rest  of  the  spirit  still  adhering  to  the  sides  of  the 
tube  to  drain  down  to  the  column.  If  this  method  of 
restoring  union  is  unsuccessful,  gentle  heat  should  be 
applied  very  carefully  to  the  end  of  the  tube  where  the 
detached  portion  of  the  spirit  is  lodged,  so  as  to  drive  it 
towards  the  column. 

The  minimum  temperature  of  the  twenty-four  hours 

generally  occurs  some  time  before  the   sun  rises.     The 

The  mean    mean  temperature  is  calculated  by  taking  the  average  of  the 

tempera-     niaximum  and  mmimum  readings,  which  is  so  near  the  true 

ture.  . 

mean  as  to  be  practically  correct.  It  is  almost  as  import- 
its  daily  ant,  from  a  public  health  point  of  view,  to  note  the  daily  range 
range.  ^j,  ^g^^^g^^^^^^.g  g^g  ^q  obscrvc  the  cxtrcmcs  to  which  the  tem- 
perature occasionally  reaches.  The  mean  daily  range  of 
temperature  is  obtained  by  deducting  the  average  dally 
minimum  from  the  average  daily  maximum  temperatures. 
Theimome-  The  tlicrmometers  which  have  been  adverted  to  being 
employed  to  indicate  the  temperature  of  the  air  in  the 
shade,  it  is  necessary,  if  we  would  obtain  correct  informa- 
tion, to  protect  them  from  the  sunlight,  wet,  etc.,  whilst 
at  the  same  time  permitting  the  freest  access  of  air. 
Accordingly,  cases,  called  thermometer  stands,  of  which 


ter  stands. 


THE    TEMPERATURE    OF    THE    AIR 


413 


there  is  a  great  variety,  are  employed,  in  which  the  instru- 
ments are  suspended.  There  are  Lawson's,^  Glaisher's,^ 
Martin's,^  James',^  Morris',^  Stevenson's,^  Griffith's,^  Stow's,*' 
Welsh's  Kew  standard,'^  and  Pastorelli's'^  stands. 

The  stand  below  depicted  resembles  Stow's  more  than 
the  other  thermometer  stands,  but  is  superior. 


Fig.  63. 


{a  a  a  a)  The  uprights.  If   by  f  inch,  serve  for  the 
suspension  of  the  maximum  and  minimum  thermometers. 


Fig.  64. 


1  Described  in  Met.  Mag.,  October  1868,  p.  127. 

2  Described  in  Met.  Mag.,  November  1868,  p.  155. 

3  Described  in  Met.  Mag.,  December  1868,  p.  169. 
^  Described  in  Met.  Mag.,  December  1868,  p.  170. 
^  Described  in  Met.  Mag.,  January  1869,  p.  187. 

6  Described  in  Met.  Mag.,  February  1869,  pp.  1,  2,  3,  and  4. 

7  Described  in  Met.  Mag.,  March  1869,  pp.  17,  18,  and  19. 


414 


THE    TEMPEKATUEE    OF    THE    AIR 


Solar  Maxi- 
mum. 


Fig.  65. 


(b)  Piece  of  thin  board  J  inch  thick,  against  which  Mason's 
hygrometer  is  fixed.  It  stands  in  the  centre  of  the  interior 
at  an  equal  distance  from  the  front  and  back  of  the  stand. 
I  have  three  of  these  stands,  and  have  but  one  fault 
to  find  with  this  form,  which  is 
apparently  inseparable  from  every 
thermometer  stand  that  has  yet  been 
devised.  When  the  rain  is  blown 
against  the  front  or  back  of  the  stand 
from  the  north  or  south,  the  thermome- 
ters are  liable  to  receive  a  wetting. 
Thermometer  stands  should  always  be  fixed  in  an  open 
place,  far  away  from  buildings  and  trees,  so  as  to  face  due 
north,  and  so  that  the  bulbs  of  the  thermometers  shall  be 
at  a  distance  of  exactly  4  feet  above  the  ground. 

4.  Solar  Maximum  Eadiation 
TJieriiiomder,  —  Comparative  ob- 
servations with  solar  radiation 
thermometers  have  been  in  the 
past  distinguished  for  their  dis- 
crepancy, due  in  part  to  imper- 
fect construction  of  the  instru- 
ment, and  partly  to  the  want  of 
uniformity  in  mounting  and  ob- 
serving it. 

The  most  modern  and  best 
thermometer  of  this  class  has  its 
bulb  and  one  inch  of  its  stem 
of  a  dull  black.  Its  jacket  is 
provided  at  each  extremity  with 
a  platinum  wire  to  test  by  the 
aid  of  a  Euhmkorff's  coil  the 
degree  of  rarefaction  of  the  air. 
If  the  interior  of  the  jacket  be  perfectly  clean,  free  from 
moisture,  and  sufficiently  exhausted,  a  pale  white  phos- 


FiG.  66. 


i 


THE    TEMPEKATUEE    OF    THE    AIR 


415 


phorescent  light,  with  faint  stratifications  and  an  appear- 
ance of  transverse  bands,  will  be  visible.  Mr.  Stow  has 
drawn  up  the  following  suggestions  for  observers,  which 
have  been  almost  universally  adopted : — 

1.  Adjust  the  instrument   4  feet  above   the  ground 

in  an  open  space,  with  its  bulb  directed  to- 
wards the  S.E.  It  is  necessary  that  the  globular 
part  of  the  external  glass  should  not  be  in 
contact  with,  or  very  near  to  any  substance, 
but  that  the  air  should  circulate  round  it  freely. 
Thus  placed,  its  readings  will  be  affected  only  by 
direct  sunshine,  and  by  the  temperature  of  the  air. 

2.  One  of  the  most  convenient  ways  of  fixing   the 

instrument  will  be  to  allow  its  stem  to  fit  into 
and  rest  upon  two  little  wooden  collars  fastened 
across  the  ends  of  a  narrow  slip  of  board,  which 
is  nailed  in  its  centre  upon  a  post,  steadied  by 
lateral  supports. 

3.  The  difference  between  the  maxima  in  sun  and  shade 

is  a  measure  of  the  amount  of  solar  radiation. 
It   has    been   found   that   solar   radiation   attains   its 
maximum  in  most  parts  of  the  country  during  May,  and 
its  minimum  during  December,  and  that  it  is  greater  on 
the  western  than  on  the  eastern  side  of  England.-^ 


Fig.  67. 


6.   Terrestrial    Minimum    Thermometer. — The     spirit  Terrestrial 
self-registering  minimum  with  a  bifurcated  bulb,  exactly 

1   Vide  "Solar  Radiation,  1869-74,"  by  Rev.  F.  W.  Stow,  in  Quarterly 
Journal  of  Meteorological  Society,  October  1874. 


416 


THE    TEMPEEATUEE    OF    THE    AIE 


similar  to  the  minimum  thermometer  for  shade  tempera- 
tures, with  a  substitution  of  a  jacket  for  protection  in 
place  of  a  porcelain  scale  and  hard  wood  back,  is  an 
excellent  instrument. 

This  thermometer  is  exposed  on  grass  which  is  kept 
closely  cut,  and  should  be  surrounded  by  some  arrange- 
ment for  protecting  it  from  dogs  and  other  animals.  A 
circular  wire-fence,  similar  to  that  depicted  in  Fig.  68,  is 
the  best  with  which  I  am  acquainted. 

The  obscurity  produced  by  a  condensation  of  moisture 
within  the  jacket,  and  the  destruction  of  the  material  em- 


FiG.  68. 


ployed  for  rendering  apparent  the  di'sdsions  on  the  stem 
from  the  same  cause,  have  sorely  troubled  observers  in 
the  past. 

As  received  from  the  instrument  maker  a  terrestrial 
minimum  thermometer  is  generally  attached  to  its  jacket 
by  a  stuf&ng  of  strips  of  indiarubber. 

Many  remedies  have  been  proposed.  A  packing  of 
chloride  of  calcium,  or  of  putty  and  sealing-wax,  or  a  bored 
cork  painted  over  on  its  exterior  with  two  or  three  layers  of 
asphalte,  or  an  air-tight  ground  joint.  Some  have  bored 
a  hole  at  the  closed  end  of  the  jacket,  and  others  have 
discarded  the  jacket  altogether. 

I  would  recommend  that  this  last-named  plan  be 
adopted,  or  that  a  bored  indiarubber  cork  be  employed, 


THE    TEMPERATURE    OF    THE    AIR 


417 


painted  externally  with  several  coats  of  asplialte,  or  that 
the  thermometer  be  fitted  to  the  jacket  like  a  stopper  to 
a  bottle.  In  either  case  the  markings  on  the  stem  should 
be  rendered  indelible,  in  the  manner  described  on  page 
420. 

Every  thermometer  should  be  numbered  and  graduated 
on  the  stem,  and  should  be  verified  by  comparison  with 
standard  instruments. 

A  special  department  at  the  Kew  Observatory  occupies 
itself  with  the  verification  of  meteorological  instruments, 
charging  a  small  fee  for  the  labour.  No  one  should  buy 
a  thermometer  or  barometer  unless  it  is  provided  with  a 
recent  certificate  of  the  verification  of  the  same. 

Proof  of  the  Necessity  for  the  Verification  of  ^z,ermo- verification 
meters. — The  inaccuracies  in  the  readings  of  thermometers,  meters. 
which  render  a  verification  of  all  a  necessity,  are  due 
partly  to  the  difference  in  the  diameter  of  the  bore 
throughout  their  entire  length,  which  defect  appears  to  be 
inseparable  from  their  manufacture,  and  partly  to  the 
tendency  which  thermometers  have  to  read  higher  from 
age. 

It  is  sometimes  difficult  indeed  to  find  two  thermo- 
meters, out  of  a  large  number,  that  read  exactly  alike.  Here 
is  a  certificate  of  verification  from  the  Kew  Observatory, 
which  belongs  to  a  thermometer  in  my  possession : — 


32°      . 

0-0 

42°       . 

0-0 

52°      . 

.      +0-1 

62°      . 

.      -0-1 

72°      . 

.      +0-1 

N.B. — "WT:ien  the  sign  of  the  correction  is  -f-  the 
quantity  is  to  be  added  to  the  observed  scale  reading,  and 
when  —  to  be  subtracted  from  it. 

They  may  in  truth  be  likened  to  human  faces,  for 
scarcely  two  are  to  be  found  very  closely  resembling  one 

2  E 


418 


THE    TEMPEEATUEE    OF    THE    AIE 


another.  A  mercurial  maximum  thermometer  was  some 
time  ago  purchased  by  one  of  my  friends  of  each  of  the 
most  eminent  meteorological  instrument  makers.  They 
were  compared  together,  and  all  found  to  differ  from  each 
other  in  their  readings. 

Mr.  Alexander  Buchan  states  ^  that  he  once  compared 
a  number  of  first-class  high-priced  thermometers,  every 
one  of  which  was  from  1'2°  to  1'7°  too  high. 

Some  thermometers  have  been  offered  to  the  public 
with  the  assurance  that  "  every  instrument  is  carefully 
verified  by  a  Kew  standard  thermometer";  which  simply 
means  a  well-made  thermometer  that  has  been  verified  at 
the  Kew  Observatory — one,  in  fact,  whose  errors  are 
known.  A  thermometer  which  had  been  thus  verified 
and  declared  free  from  error  was  sent  by  me  to  this  ob- 
servatory. The  certificate  returned  with  it  contained  the 
following  corrections  : — 

At    90° -0-2 


95' 
100' 
105' 


-0-2 
-0-1 
-0-0 


Another  thermometer  sent  out  by  a  difierent  maker  is 
in  my  possession  which  was  "guaranteed  accurate  in  its 
indications,  having  been  compared,  degTce  by  degTee,  with 
a  standard  thermometer  verified  at  Kew."  It  is  about 
•4  of  a  degree  in  one  part  of  the  scale,  and  '5  in  another 
part,  higher  than  is  correct. 

Here  is  the  certificate  of  a  third  thermometer,  which 
was    supposed   to    be   perfectly  accurate    before  returned 


trom  tne  Hew  Ubservatory  : — ■ 

At     85°    . 

-0-3 

„      90°    . 

-0-4 

„      95°    . 

-0-5 

„    100°    .          . 

-0-4 

„    105°    .          .          .          . 

-0-4 

^  Randy  Book  of  ihteorology. 

Blackwood. 

1867. 

THE    TEMPERATURE    OF    THE    AIR  419 

It  is  not  by  any  means  an  easy  matter  to  verify 
thermometers  with  precision.  The  verification  can  only 
be  satisfactorily  conducted  by  means  of  instruments 
specially  adapted  for  the  purpose,  such  as  are  to  be  found 
in  the  great  observatories. 

It  should  be  done,  moreover,  with  the  greatest  care, 
by  men  who  are  accustomed  to  the  work. 

The  following  memoranda  for  purchasers,  which  were 
published  in  a  paper  ^  read  before  the  British  Medical 
Association  in  1869,  may  be  advantageously  repeated: — 

{a)  Mercurial  thermometers  which  are  two  or  three 
years  old  are  always  to  be  preferred. 

(b)  No  instrument  should  be  bought  without  a  certificate 
from  an  observatory  of  its  recent  verification. 

Mercurial  thermometers  are  liable  to  read  higher  than 
is  correct  through  age ;  and  this  change  especially  occurs 
during  the  year  or  two  immediately  succeeding  their 
period  of  construction.  The  bulb,  ha^dng  been  formed  by 
the  action  of  heat,  undergoes  contraction  after  its  manu- 
facture, the  fibres  of  the  glass  taking  some  little  time  to 
assume  their  permanent  position.  Hence  it  has  been 
usual  amongst  some  makers  of  meteorological  instruments 
to  lay  down  their  thermometers,  like  their  port,  for  im- 
provement with  age,  before  engraving  the  scale  on  their 
stems.  "  By  quite  a  recent  discovery  in  the  manufacture 
of  these  instruments,"  writes  one  who  sells  thermometers, 
"  the  glass  bulb  of  the  thermometer  is  reduced  to  its 
ultimate  degree  of  contraction  before  the  stem  is  divided, 
thus  obviating  the  necessity  of  keeping  the  tubes  fiUed 
for  the  space  of  one  or  two  years  before  dividing  them, 
and  rendering  it  possible  to  make  an  absolutely  accurate 
instrument  in  a  week"  With  the  object  of  ascertaining 
the  truth  of  this  statement,  I  made  a  careful  examination 

^  " Remarks  on  Clinical  Thermometers." — Medical  Times  and  Gazette, 
October  16,  1869. 


meters. 


420  THE    TEMPERATUEE    OF    THE    AIR 

of  one  of  these  thermometers,  and  discovered  that  it  was 
incorrect.  Its  readings  were  about  two-fifths  of  a  degi'ee 
too  high. 

The  verification  of  a  two  or  three-year  old  mercurial 
thermometer  at  an  observatory  should  not  be  relied  on  as 
a  guarantee  of  its  perpetual  accuracy.  The  authorities  of 
the  Kew  Observatory  consequently  append  to  their  certi- 
ficates the  following,  amidst  other  notes  : — "  This  instru- 
ment ought,  at  some  future  date,  to  be  again  tested  at  the 
melting-point  of  ice,  and  if  its  reading  at  that  point  be 
found  different  from  that  now  given,  an  appropriate  cor- 
rection ought  to  be  applied  to  all  the  above  points." 
Markings  of  The  markings  on  the  stem  of  thermometers,  which 
thermo-  indicate  the  degrees  and  parts  of  degTees,  are  exceedingly 
apt  to  crumble  away  and  disappear  after  but  a  short 
exposure  to  the  air,  for  the  reason  that  instrument  makers 
do  not  know  of  a  durable  composition  with  which  to  form 
them.  The  markings  of  the  divisions  may  be  replaced  by 
the  observer  in  either  of  the  following  modes : — 

The  stem  of  the  thermometer,  having  been  thoroughly 
cleansed  by  scrubbing  it  with  an  old  tooth-brush  dipped 
in  a  mixture  of  strong  aqueous  caustic  soda  and  methy- 
lated spu'it  in  equal  proportions,  is  washed  with  water  and 
dried.  Silicate  of  soda  is  mixed  with  water  sufficient  to 
produce  a  syrupy  solution.  A  little  of  this  fluid  is 
mingled  with  some  lampblack,  so  as  to  form  a  j)aste,  which 
is  brushed  over  the  divisions  as  a  coating.  The  ther- 
mometer is  rolled  between  a  flat  piece  of  wood  and  a 
strip  of  cardboard,  so  as  to  remove  all  of  the  black  coating 
from  the  stem  except  that  which  fills  the  gTooved  lines 
of  the  divisions.  By  means  of  another  brush  dipped  in 
the  clean  syi'upy  solution  of  silicate  of  soda,  a  coating  of 
this  artificial  glass  is  rapidly  spread  over  the  whole  of  the 
stem  of  the  thermometer,  which  is  then  allowed  to  dry. 
Some  mix  with  the   s}Tupy  solution   of  sodic  silicate 


THE    TEMPEKATUEE    OF    THE    AIE  421 

some  common  precipitated  manganic  dioxide,  to  which  a 
little  lampblack  has  been  added. 

Others  smear  over  the  scale  of  divisions  on  the  stem 
some  compound  of  lead,  converted  into  a  paste  with  a 
solution  of  silicate  of  soda.  The  paste  which  does  not  fill 
the  lines  is  rapidly  removed  by  rubbing  the  stem  of  the 
instrument  between  two  smooth  surfaces.  Tlie  divisions 
containing  the  paste  are  then  brushed  over  with  a  little 
ammonium  sulphide,  which  forms  with  the  lead  the  black 
sulphide  of  lead. 


CHAPTEE    XXXV 

3. THE    HYGEOMETEIC    CONDITION    OF    THE    AIE 

Moisture  of  The    hygTometric    state    of    tlie    air    is    determined    by 
by  ndi?"'^'' — ^■^^>  ^^  estimation,  by  the  help  of  the  rain-gange,  of 
gauge,  hy-   the  amount  of  water  which  readies  the  earth  in  the  form 
and"spe"tro- of  rain,  hail,  snow,  and  fog;    2d,  a  consideration  of  the 
scope.         indications  of  the  hygrometer,  an  instrument  for  deter- 
mining the  amount  of  aqueous  vapour  present  in  the  air, 
near  the  surface  of  the  earth ;  and  Sd,  a  rough  estimate 
of  the  degree  of  development  of  the  atmospheric  lines  of 
the  solar  spectrum  as  shown  by  a  spectroscope. 

The  amount  of  moisture  in  the  air  cannot  be  deter- 
mined by  either  of  these  instruments  separately,  but  is 
exhibited  by  the  combined  information  afforded  by  them. 
A  month's  rainfall  may  simply  imply  the  amount  of  rain 
which  fell  on  one  excessively  wet  day,  the  remaining  days 
of  the  month  being  dry  and  fine.  The  air  is  frequently 
very  moist,  even  when  no  rain  falls.  The  rainfall  of 
New  York  is  nearly  double  that  of  London,  yet  the 
relative  humidity  of  the  air  of  New  York  is  much  less 
than  that  of  London.  Wliilst  the  number  of  aqueous 
-  lines  in  the  solar  spectrum  between  D^  and  D^  at  New 
York,  corresponding  with  the  weight  in  grains  of  aqueous 
vapour  in  each  cubic  foot  of  air,  is  at  its  minimum  in 
January,  and  at  its  maximum  in  August  or  September, 
Dr.  D.  Draper  shows  that  the  relative  humidity  of  New 
York  reaches  its  maximum  of  96  in  January,  instead  of 
in  August  or  September. 


THE    HYGROMETRIC    CONDITION    OF    THE    AIR 


42; 


The  degree  of  humidity  of  the  air  is  affected  by  many 
circumstances — such  as  direction  of  the  wind,  temperature, 
season  of  the  year,  distance  from  masses  of  water,  and 
confiejuration  of  the  land  over  which  it  lies. 

A  Bain  Gauge,  quite   good   enough  for  all  practical  Rain  Gauge. 
purposes,  can  be  purchased  for  about  half  a  guinea,  the 
glass  measure,  which  is  divided  into  Y^^ths  of  an  inch, 
being  included. 

It  should  be  fixed,  by  means  of  four  or  more  wooden 
stakes,  firmly  into  the  ground,  so  that  its  summit  is  12 
inches  above  the  surface.      The  farther  removed  the  site 

is  from  buildings  and  trees  the 
better.  It  should  always  be 
as  far  from  a  neighbouring 
object  as  that  object  is  high. 
Snow  should  be  melted  be- 
fore it  is  measured. 

Printed  directions  for  mak- 
ing observations  generally  ac- 
company these  instruments. 
Any  information  as  to  the 
estimation  of  the  rain  is 
^  freely  given  by  Mr.  Symons, 
*^''  of    Camden    Square,    London, 

Rain  Gauge.    Fia.  69.  ^^j^^      -^     ^^     ^j^^     j^^^^     ^^      ^^ 

rainfall  registration  in  this  country.  Forms  for  its  regis- 
tration may  be  obtained  from  Mr.  Stanford,  Charing 
Cross,  London. 

Dr.  Trench,  the  late  Medical  Officer  of  Health  for 
Liverpool,  was  strongly  impressed  with  the  belief. that 
there  is  an  inverse  ratio  between  the  rainfall  and  the 
amount  of  mortality  from  infantile  summer  diarrhoea. 
If  this  ;  disease  is  dispersed,  or  rendered  less  virulent  by 
an  excessive  rainfall,  it  is  often  superseded  by  catarrhal 
and  rheumatic   affections,   which,   although   less    mortal, 


424 


THE    HYGEOMETEIC    CONDITION    OF    THE    AIE 


Hygro- 
meters. 


are  often  exceedingly  intractable,  and  sometimes  lead  to 
serious  results. 

The  Hygrometer. — The  amount  of  aqueous  vapour 
present  in  the  air  is  determined  by  instruments  called 
hygrometers,  of  which  there  is  a  great  variety.  Eey- 
nault's  and  Mason's  hygrometers  are  generally  preferred ; 
but,  as  the  working  of  the  former  instrument  with  ether 
and  an  aspirator  is  troublesome,  the  latter  has  almost 
entirely  supplanted  it  in  everyday  practice.  It  consists 
of  two  verified  thermometers,  fixed  side  by  side ;  the 
bulb  of  one  being  kept  always  damp  by  a  covering 
of  muslin  connected  with  a  little  reservoir  of  distilled 
water  by  means  of  a  lamp  wick.  Great  mistakes  are 
commonly  made  in  the  adjustment  of  the  muslin,  lamp 
wick,  and  water  reservoir.  I  have  seen  a  hygrometer 
in  the  observatory  of  a  Philosophical  Society  with  the 
w^et  bulb  arranged  in  the  mistaken  manner  here  depicted  : 


Mason's 
hygro- 
meter. 


Fig.  70. 


The  Improper  Mode.  The  Proper  Mode. 

Bulbs  of  Mason's  Hygrometers. 

In  the  first  sketch  the  wet  bulb  is  smothered  in  wet 
muslin,  to  which  is  attached  a  piece  of  lamp  wick  as 
large  as  one's  little  finger,  whilst  close  below  the  bulb 
is  an  open  vessel  fuU  of  water.  Every  provision  would 
seem  to  be  made  here  for  producing  an  artificial  local 
dampness  of  air  around  the  bulb,  and  for  rendering  it 
simply  impossible  that  the  thermometer  should  really 
furnish  us,  by  indicating  the  temperature  of  an  evapor- 


THE    HYGROMETKIC    COXDITION    OF    THE    AIR         425 

ating  surface,  with  the  true  hygrometric  state  of  the  air 
in  the  neighbourhood. 

The  finest  musHn,  which  generally  contains  starch, 
should  be  boiled  in  distilled  water  to  extract  it.  Lamp 
wick  should  be  boiled  in  distilled  water  and  a  little 
carbonate  of  soda  to  remove  all  grease.  The  smallest 
thread  of  lamp  wick  that  will  keep  the  muslin  per- 
manently damp  should  be  employed,  and  the  little 
reservoir  of  water  should  be  fixed  away  from  the  bulb, 
so  as  not  to  create  a  local  artificial  climate. 

The  first  drawing  represents  the  ignorant  and  care- 
less use,  and  the  second  drawing  the  intelligent  employ- 
ment, of  the  hygrometer. 

The  hygrometer  is  fixed  against  a  thin  board  that  occu- 
pies the  centre  of  the  thermometer  stand.  Like  the  other 
shade  thermometers  it  should  face  the  north.  If  the  air  is 
saturated  with  moisture  there  is  little,  if  any,  difference 
between  the  readings  of  the  dry  and  wet  bulb  thermometers. 
The  readings  of  the  wet  bulb  are,  as  a  rule,  lower  than 
those  of  the  dry  bulb  thermometer.  The  generally  accepted 
statement  that  the  greater  the  difference  between  the  dry 
and  wet  bulbs  the  less  is  the  amount  of  watery  vapour 
present  in  the  air,  requires  some  qualification. 

An  increase  of  temperature,  by  expanding  the  air, 
and  thus  separating  the  particles  farther  from  each  other, 
increases,  whilst  a  fall  of  temperature,  by  drawing  them 
closer  together,  diminishes  the  capacity  of  the  air  for 
moisture.  Air  of  a  temperature  of  57*2  dry  bulb,  and 
51  wet  bulb,  with  a  relative  humidity  of  64,  may  contain 
exactly  the  same  amount  of  vapour  in  grains  per  cubic 
foot  (3 '4)  as  air  of  a  temperature  of  70*5  dry  bulb,  and 
56*8  wet  bulb,  with  a  relative  humidity  of  42.  The 
semi-diurnal  rise  of  temperature  is  more  frequently  ac- 
companied by  an  increased  capacity  of  the  air  to  absorb 
moisture  than  an  actual  increase  in  its  amount. 


426 


THE    HYGEOMETPJC    CONDITIOX    OF    THE    AIR 


The  relative  humidity  of,  or  percentage  of,  moisture  in 
the  air  is  afforded  by  reference  to  a  table  to  facilitate 
calculation.  ^ 


One  of  the  best,  if  not  the  best,  hygrometer  for 
popular  use,  as  it  requires  no  tables  and  calculations, 
is  one  that  was  designed  by  Mr.  Lowe  of  Boston,  U.S., 
and  is   employed   in   France.      It   is    especially   adapted 

^  The  fullest  information  as  to  the  use  of  Mason's  hygrometer,  and 
the  calculation  of  the  dew  point,  etc.,  is  to  he  found  in  James  Glaisher's 
Hycjromctric  Tables,  adapted  to  the  dry  and  wet  bulb  thermometers. 
Third  edition.     Taylor  and  Francis,  Fleet  Street,  London. 

The  tables  prepared  by  William  Bone,  which  are  obtainable  from 
Negretti  and  Zambra,  are  also  useful. 


THE    HYGEOMETPJC    CONDITION    OF    THE    AIR         42  7 

for  the  sick  room,  as  it  can  be  easily  managed  by  an 
intelligent  nurse  in  accordance  with  the  instructions  of 
the  physician  (fig.  71). 

It  consists  of  two  thermometers  precisely  alike,  the 
bulb  of  one  being  dry  and  the  other  kept  always  moist. 
On  the  inner  side  of  the  dry  bulb  scale  is  a  third  scale, 
on  which  two  indices  move  up  and  down.  In  the  central 
portion  of  the  lower  part  of  the  hygrometer  is  a  screw 
head  with  a  pointer  attached  to  it.  By  the  help  of  the 
vertical,  oblique,  and  horizontal  lines  the  relative  humidity, 
dew  point,  and  elastic  force  of  vapour  of  the  air  may  be 
seen  at  any  moment  at  a  glance.  The  instructions  as  to 
the  mode  of  working  the  instrument  are  thus  given  in 
the  Meteorological  Magazine  of  December  1877  : — 

"(1)  Eead  the  dry  bulb  thermometer,  and  raise  the  Lowe's 
screw  head  in  order  to  set  the  upper  index  on  the  extra  j^^^' 
scale  at  the  dry  bulb  temperature ;  (2)  read  the  wet 
bulb,  and  turn  the  screw  head  until  the  lower  index  is  at 
the  wet  bulb  temperature.  The  extremity  of  the  long 
hand  will  then  point  to  {a)  the  relative  humidity ;  (&)  the 
dew  point ;  and  (c)  the  elastic  force  of  vapour,  according 
as  one  reads  the  vertical,  oblique,  or  horizontal  lines." 
The  only  objection  to  this  instrument  is  that  very  common 
one  which  has  already  been  adverted  to  in  referring  to 
]\Iason's  hygrometer,  as  to  the  position  of  the  reservoir  of 
water,  etc.      This  defect  can,  of  course,  be  easily  removed. 

Tlie  Spectroscope. — Wliilst  hygrometers  indicate  therheSpectr 
degree  of  moisture  of  the  air  around  them,  the  spectroscope  ^*^°^^" 
furnishes  us  with  a  means  of  roughly  estimating  that 
contained  in  the  higher  regions  of  the  atmosphere.  The 
water  lines  in  the  solar  spectrum  are  very  numerous, 
especially  in  the  red  j^ortion.  The  principal  aggregation 
of  them  forms  what  is  known  as  the  atmospheric  zone  or 
"  rain-band,"  on  the  red  side  of  D.  In  Angstrom's  atlas 
more  than  50  lines  may  be  easily  counted  in  this  zone. 


428         THE    HYGROMETEIC    CONDITION    OF    THE    AIR 

There  is  a  minor  rain-band  between  &  and  F,  which  he 
describes  as  "  tres  forte  pendant  les  mois  d'ete,"  and  which 
has  been  named  the  "  Maxwell  Hall's  Jamaica  Eain-Band." 
Prof.  J.  P.  Cooke  of  Cambridge,  Massachusetts,  U.S.,  confin- 
ing his  attention  -^  to  the  study,  by  means  of  a  powerful 
spectroscope,  respecting  the  relation  between  the  number  of 
interstitial  lines  in  the  otherwise  empty  space  bisected  by 
the  solar  Nickel  line  between  D^  and  D^  (for  D  discloses 
itself  as  a  double  line  under  a  high  power),  and  the  weight 
of  aqueous  vapour  per  cubic  foot  of  air,  found  an  augmenta- 
tion of  their  number  as  the  weight  of  water  gas  increased 
from  "81  to  6 '5 7  grs.  per  cubic  foot.  Prof  Piazzi  Smyth  has 
often  counted  1 1  or  more  of  these  water  lines  in  this  space.^ 
Without  diving  deeply  into  this  subject  by  the  help  of 
powerful  instruments,  we  shall  find  that  much  information 
is  afforded  by  a  practical  acquaintance  with  a  small  waist- 
coat-pocket spectroscope,  which  enables  the  observer  to  study 
the  changes  in  the  apparent  thickness  of  the  Fraunhofer 
line  D  in  the  solar  spectrum,  and  compare  its  size  and  dis- 
tinctness with  the  unchangeable  lines  E,  b,  and  P,  on  the 
less  refrangible,  or  green  and  violet  side  of  the  spectrum. 
What  has  been  described  by  Prof.  Piazzi  Smyth  as  "the  rain- 
band"  is  the  blurred  appearance  on  the  red  side  of  D,  which 
becomes  more  or  less  distinct  in  proportion  to  the  amount 
of  moisture  in  the  air  and  to  the  probability  of  rain  falling. 
The  line  D  is  seen  by  a  small  spectroscope  to  separate 
the  red  from  the  yellow,  and  F  appears  to  be  in  a  position 
where  the  green  merges  into  the  violet  parts  of  the  spectrum. 
The  degree  of  visibility  of  the  fine  lines  in  the  green  part 
of  the  spectrum  between  D  and  E  is  also  worth  noting,  as 
when  rain  is  imminent  they  become  less  distinct.  On  the 
yellow  side  of  D  are  often  to  be  seen,  especially  when  the 
sun  is  on  the  horizon,  "  low  sun-bands  "  which  should  be  dis- 

^  American  Journal  of  Science,  ]S'ovem'ber  1865. 
-  The  Visual  Solar  Sj^edrum. 


THE    HYGROMETPJC    CONDITION    OF    THE    AIR 


429 


regarded  in  rain  prediction.  The  line  D,  with  the  attached 
"  rain-band/'  may  be  compared  as  to  its  thickness  and  dis- 
tinctness with  the  Fraunhofer  lines  E,  5/  and  F,  forming  as 


Red 


l^llcw         Green,  Vtcleb 

Fig.  72. 


they  do  three  grades,  or  standards  of  comparison,  a  thickness 
equal  to  F  showing  a  large  excess  of  moisture  in  the  air.^ 

1  6  is  ill  reality  a  double  line,  but  is  seen  with  difficulty  as  such  if  a  spec- 
troscope of  very  moderate  dispersion,  like  that  recommended,  be  employed. 

^  When  the  information  afforded  by  the  spectroscope  is  supplemented 
by  that  given  by  the  thermometer,  the  probability  or  otherwise  of  the 
condensation  of  the  moisture,  in  the  form  of  rain,  hail,  or  snow,  at  or 
around  the  place  of  observation  may  be  estimated  with  some  approach  to 
precision.  Dr.  H.  E..  Mill  has  offered  to  the  public  the  following  guide, 
which  may  be  useful  to  weather  prophets.  It  refers  to  appearances  pre- 
sented by  a  small  Hilger's  spectroscope,  and  the  rules  for  prediction  are 
based  on  observations  made  at  Edinburgh. 


Thickness  and  distinctness  of  line  D. 

Temperature. 

Prediction. 

le.  5 

No  rain. 

,, 

Below  40°  F. 

Possibly  rain. 

=  h 

40°  F. 

Rain. 

h 

Between  40°  &  45° 

Probably  rain. 

b 

„      45°  &  50° 

Probably  no  rain. 

h 

Above  50° 

No  rain. 

gr.  h,  le.  F 

.  (thin  lines  distinct) 

Below  45° 

Probably  no  rain. 

Above  45° 

No  rain. 

;>          )  J 

(thin  lines  indistinct) 

Below  60° 

Probably  rain. 

,,          ,, 

))               )) 

Above  60° 

Probably  no  rain. 

=r. 

Pain. 

gr.  F. 

. 



Much  rain. 

le.  signifies  less  than.  gr.  signifies  greater  than. 
Those  who  have  not  worked  at  the  spectroscope  in  connection  with 
meteorology  will  find  information  on  this  subject  in  an  article  entitled 
"Rain-band  Spectroscopj',"  by  Professor  P.  Smyth,  in  the  Transactions 
Scottish  Meteor.  Socy.,  Nos.  51-54,  and  in  The  Eain-bancl  (Hilger,  1883), 
by  H.  R.  Mill,  and  also  in  A  Flea  for  the  Rain-hand,  and  the  Rain-hand 
Vindicated,  by  J.  R.  Capron,  published  by  Stanford  of  Charing-Cross,  1886. 


CHAPTER    XXXVI 

4. THE    DIRECTION    AND    STRENGTH    OF    THE    WIND 

The  directio7i  of  the  wind  is  easily  ascertained  by  noting 
the  movements  of  the  lowest  stratum  of  clouds.  The 
upper  strata  of  clouds  are  sometimes  to  be  seen  travelling 
in  an  opposite  direction  to  that  in  which  the  lower  are 
moving. 

The  strength  of  the  wind  is  estimated  by  its  velocity 
Anemo-  or  prcssurc.  Instruments  named  anemometers  are  em- 
pressure  ployed  to  register  its  velocity,  and  pressure  plates  its 
plates.        force. 

The  belief  of  meteorologists  in  anemometers  has 
suffered  a  rude  shock  by  the  investigation  made  by  the 
Eev.  Fenwick  Stow,  on  a  simultaneous  comparison  of  the 
behaviour  of  different  anemometers.^  He  discovered  that 
the  results  were  discordant,  and  that  the  indications  of 
the  only  instrument  which  comes  within  the  reach  of  the 
purses  of  most  of  us,  namely,  Robinson's  cup  anemometer, 
are  very  fallacious. 

Pressure  plates  are  open  to  several  objections,  and  are 
generally  costly  contrivances,  arranged  with  vanes,  so  as 
to  keep  the  surface  of  the  plate  always  at  right  angles  to 
the  flow  of  the  wind. 

The  cheapest  and  simplest  which  I  have  seen  is  one 

^  "On  Large  and  Small  Anemometers."  —  Quarterly  Journal  of  the 
Meteorological  Society,  April  1872. 


THE    DIRECTION    AND    STRENGTH    OF    THE    WIND     431 

thcat     has     recently    been    introduced     by    Mr.    Thomas 
Stevenson,  which  can  be  obtained  for  24s.^ 

A  is  a  wood  box,  f  inch  thick,  attached  to  the  top  of 
a  stake  fixed  in  the  ground,  which  turns  with  the  wind 
on  a  vertical  axis. 


Fig.  73. 


&  is  a  small  disc,  fixed  on  a  light  brass  tube,  ^  mch  in 
diameter,  which  rests  on  two  brass  rollers. 

B  is  a  larger  disc,  fixed  on  a  light  brass  tube,  ^  inch 
in  diameter,  which  rests  on  two  brass  rollers. 

When  acted  on  by  the  wind  the  brass  spring  >S^  is 
lengthened,  the  maximum  elongation  being  recorded  by  a 
fine  thread  attached  to  the  rod,  which  is  pulled  through 
a  small  hole  in  a  brass  plate  {t)  fixed  to  the  side  of  the 
box.  The  rods  are  graduated  by  weights,  each  division 
corresponding  to  the  elongation  of  the  spring,  due  to  a 
weight  of  1  ounce. 

"  To  ascertain  the  maximum  elongation  that  has 
taken  place  in  the  observer's  absence,  press  the  thread 
against  t,  then  push  in  the  disc  until  the  part  of  the 
thread  which  had  been  drawn  through  the  hole  in  t  is 
again  drawn  'taut,'  and  read  off  the  result  from  the 
graduated  tube." 

^  Scottish  Meteorological  Journal,  July  1874-July  1875,  p.  266. 


432     THE    DIEECTIOX    AXD    STEEXGTH    OF    THE    WIND 


Pressure  in  lbs.  per  sq.  ft. 

Remarks. 

July  3 

2-54 

4 

7-50 

Stormy  winds  vrith.  sudden 
gusts. 

5 

3-44 

7 

1-05 

8 

•80 

31 

•62 

Aug.  1 

1-54 

2 

12-00 

Weather  described  in  news- 

paper  as  a  heavy  gale. 

"When  the  disc  is   6  inches,  the  factor  for  reducing  the  diAdsions 
(due  to  pressure  of  1  oz.),  to  the  stand- 
ard of  lbs.  to  the  sq.  ft.  is  .      '318 
Do.                3                        do.                   do.  .    1-273 
Do.                li                     do.                   do.                 .      5-09 


This  variety  of  pressure  gauge  has  been  constructed  for 
storm  stations  with  one  disc  of  3  inches  diameter,  and  the 
other  1^  inch,  but  admittmg  of  a  6 -inch  one  being  put 
on  at  any  time  when  the  winds  are  light. 

One  great  objection  to  these,  as  to  ahnost  all  other 
wind-pressure  plates,  is,  that  they  only  move  in  a 
horizontal  line.  Supposing  the  wind  to  descend  upon 
them,  or  ascend  towards  them,  in  sudden  gusts,  they  do 
not  feel  and  therefore  cannot  register  its  force. 
Table  for  I  havc  bccn  in  the  habit  of  employing  the  accom- 

roughesti-  panyincT  table  (extracted  from  Buchan's  Metcoroloay)  for 

mate  of  force  •'^       ^^       o  \  <^t// 

of  wind.  many  years,  and  think  it  can  hardly  be  improved  upon  as 
a  guide  to  the  formation  of  a  rough  estimate.  The  scale 
is  0  to  6,  0  representing  a  calm,  and  6  a  hurricane, — 
a  violence  of  wind  which  i-s  unknown  in  this  country. 


THE    DIEECTIOX    AND    STKENGTH    OF    THE    WIXD      433 


m 

i 

s 

o    . 

id*^ 

B  ^ 

""*  -^ 

.E  3 

;_   CQ 

m"^ 

^    '-, 

-*J     tn 

w 

<o  '^ 

§  s. 

(5 

!> 

0-0 

0-00 

0-0 

01 

0-01 

1-4 

0-5 

0-25 

7-1 

1-0 

1-00 

14-1 

1-5 

2-25 

21-2 

2-0 

4-00 

28-3 

2-5 

6-25 

35-4 

Popular 
Designation. 


Calm. 
Lightest 
breath  of  air. 
Very  light  air. 
Light  air. 
Light  breeze. 

•  Fresh    , , 


3-0 
3-5 
4-0 
4-5 

5-0 

5-5 
6-0 


9-00 
12-25 
16-00 
20-25 

25-00 

30-25 
86-00 


42-4 
49-5 
56-6 
63-6 

70-7 

77-8 


Popular 
Desiguation. 


j-Very  fresh. 

1  Blowing 
J      hard. 
Blowing  a 

gale. 
Violent  gale. 
Hurricane. 


2  F 


CHAPTEE    XXXVII 

5. THE  ELECTEICAL  STATE  OF  THE  AIR 

This  subject  may  be  discussed  under  two  heads : — (1) 
As  to  the  mode  of  collecting  atmospheric  electricity  ;  (2) 
As  to  the  mode  of  determining  its  kind,  whether  positive 
or  negative,  and  its  tension. 
Mode  of  n^  Mode  of  collecting  atmospheric  electricity.    Various 

collection.  ;   /  ^  ^  ^         ^      ^   ^  ^  "^     .         ^         , 

contrivances  have  been  employed — such  as  an  insulated 
metal  point ;  a  kite ;  a  pole,  with  an  insulated  pointed 
wire,  or  bundle  of  copper  wires,  or  conducting  ball  on  its 
summit,  connected  by  an  insulated  wire  with  an  electro- 
meter ;  a  rod  with  a  burning  fuse  or  match ;  a  copper 
tube,  with  an  oil  lamp  always  burning  attached  to  its 
extremity ;  an  insulated  can  of  water,  with  a  fine  dis- 
charging tube,  dropping  minute  quantities  of  water 
through  the  air  ;^  balloons  with  wire  coverings  ;^  a 
spirit  lamp  on  an  insulated  stand ;  a  gas  jet,  so 
constructed  that  it  cannot  be  extinguished  by  the 
wind ;  etc.  etc. 

The  insulated  ca,n  of  water  is,  of  course,  useless  in 
frosty  weather,  and  troublesome  wdien  it  is  desired  to 
make  observations  at  different  places ;  otherwise  the 
water  dropper  is  a  most  convenient  apparatus. 

^  A  description  of  this  may  be  found  in  DesdmneVs  Natural  Philosophy, 
by  Professor  Everett,  part  iii.  p.  604. 

^  Noicveau  ProcMi  pour  Etudier  Villectricite  AtmospMrique,  by  M. 
Monnet.     Published  by  the  Societe  des  Sciences  Industrielles  de  Lyon. 


THE    ELECTRICAL    STATE    OF    THE    AIR  435 

Sir  Wm.  Thompson  employs  for  travelling,  in  connection 
with  his  portable  electrometer,  blotting  paper  steeped  in  a 
solution  of  nitrate  of  lead,  dried,  and  rolled  into  matches, 
which  are  attached  to  a  brass  rod  projecting  from  the 
instrument. 

(2)   Mode  of  determining  its  kind,  whether  positive  Determma- 

,•  1    -J.      J.  •  tionofits 

or  negative,  and  its  tension.  kind  and 

The  electrical  condition  of  the  air  has  been  most  tension, 
frequently  determined  in  the  past  by  the  employment  of 
an  electrometer,  which  is  figured  in  almost  every  meteoro- 
logical work  and  catalogue  of  instruments.  It  therefore 
needs  no  description,  beyond  stating  that  its  essential 
parts  are  gold  leaves  and  a  brass  rod  2  feet  long,  with 
a  lighted  fusee  composed  of  nitrate  of  lead  to  collect  the 
electricity.  As  a  glass  rod,  when  rubbed,  produces 
positive,  and  a  stick  of  sealing-wax,  when  thus  treated, 
negative  electricity,  and  as  all  bodies  similarly  electrified 
repel  each  other,  whilst  those  oppositely  electrified  attract 
one  another,  the  custom  has  been  in  employing  this 
instrument  to  apply  the  excited  sticks  in  turn,  in 
order  to  ascertain  the  kind  of  electricity  with  which 
the  gold  leaves  diverge.  It  will  indicate  the  pres- 
ence of  the  electric  fluid  on  almost  any  fine  night, 
and  will  show  by  the  aid  of  the  rod  of  glass  or 
wax  the  positive  or  negative  character  of  it,  but  the 
intensity  of  the  same  is  not  referable  to  any  accurate 
scale. 

It  is  now  almost  abandoned  for  investigations  as  to 
the  electrical  condition  of  the  atmosphere.  The  only 
instruments  with  wliich  I  am  acquainted  that  are  of  any 
service  in  these  delicate  investigations  as  to  the  nature 
and  tension  of  atmospheric  electricity  are  Sir  William 
Thompson's  portable  electrometer,^  Messrs.  Elliott  and 
Co.'s  modification  of  Thompson's  quadrant  electrometer, 
^  Obtainable  in  tbis  country  from  James  White  of  Glasgow. 


436 


THE    ELECTEICAL    STATE    OF    THE    AIR 


Peltier's  electrometer,-^  Lament's  electrometer,  and  Palmieri's 
electrometer.  Thompson's  portable  electrometer  is  easily 
managed,  but  if  it  is  once  out  of  order,  or  has  been 
neglected,  is  almost  hopelessly  ruined.  Its  price  is 
£10  :10s.     Elliott  and  Co.'s  modification  of  Thompson's 


TJ2e~Wctter  J) roppi7/ff  Collector 


I  I         VC     E 


Fig.  74. 

A.  The  needle  with  min'or.  B.  The  Leyden  jar.  C.  Electrode  in  commnnication 
■with  body  to  be  tested.  C  Electrode  in  connection  with  the  earth.  D.  Copper  vessel 
containing  water.  E.  Brass  pipe,  with  tap,  tapered  to  discharging  orifice.  P.  Glass 
stem.  G  G.  Pumice  moistened  with  sulphuric  acid.  H  H.  Brass  case  lined  with 
gutta-percha.    1 1.  Section  of  wall. 

quadrant  electrometer  is  not  at  all  portable,  but  is  cheaper, 
being  £5  :  5s.  It  requires  a  collector  which,  if  an  insulated 
can  of  water,  costs  an  extra  three  guineas.  Some  excellent 
drawings  of  the  former  or  the  portable  instrument  are  to 
be  found  in  Noad's  Students'  Text -Booh  of  Medricity, 
pages  466  and  467,  and  in  DeschctneV s  Natural  Philosophy, 
by  Professor  Everett,  part  iii.  page  593.  The  latter  has 
nowhere,  to  my  knowledge,  in  conjunction  with  the  in- 

1  Both,  obtainable  from  Messrs.  Elliott  and  Co.,  112  St.  Martin's  Lane 
London. 


THE    ELECTRICAL    STATE    OF    THE    AIR  437 

sulatecl  can  of  water  collector,  been  delineated.  Peltier's 
electrometer  has  been  employed  for  more  than  thirty  years 
at  Brussels  by  M.  Quetelet,  and  is  described  in  the 
Annuaire  Meieorologique  de  France,  1850,  page  181. 
Palmieri's  electrometer  is  hardly  known  in  this  country, 
but  is  valued  in  Italy,  Austria,  and  France.  M.  Branly's 
modification  of  Thompson's  electrometer  is  also  employed 
by  the  French. 

The  Medical  Officer  of  Health  who  contemplates  making 
a  special  study  of  this  subject — and  it  affords  in  relation 
to  health  and  disease  a  boundless  field  for  research,  which 
has  up  to  the  present  time  been  scarcely  cultivated — would 
do  well  to  acquire  a  practical  familiarity  with  the  principal 
electroscopes,  electrometers,  and  distinguishers  that  have 
been  at  various  times  in  use.  He  will  find  the  works  of 
Saussure  and  Schiibler,  of  Quetelet,^  Lament,^  Duprez, 
Thompson's  reprint  of  papers  on  electrostatics  and 
magnetism,  and  the  bulletins  of  the  Observatories  of  Kew 
and  Greenwich,  of  service.  They  contain  records  of  the 
annual,  seasonal,  monthly,  and  diurnal  changes  in  the 
electrical  condition  of  the  atmosphere  of  great  value.  A 
comparison  between  the  monthly  electrical  observations 
at  different  observatories  in  relation  to  the  development  of 
atmospheric  ozone  is  to  be  found  in  Ozone  and  Antozone, 
page  67,  etc.  M.  Mascart's  Traite  de  VElectricite  is  a 
book  which  will  be  also  found  useful  by  the  student. 

The  quality  of  the  electricity  present  in  the  air  is 
ascertained  by  observing  the  attraction  or  repulsion  of 
the  needle.  If  the  jar  is  charged  positively,  the  needle 
will  be  repelled  when  a  positive  charge  is  in  the  air,  and 

1  "  Observations  des  Phenomenes  Periodiques,"  extracted  from  M6moires 
de  I'Academie  Royal  de  Belgique,  vol.  xxix. 

"^  "  Entnommen  aus  dem  Jahresberichte  der  Miinchner  Sternwartc, 
p.  72,  iind  aus  dem  vii.  Bande  der  Annalen  der  K.  Sternwarte  zu 
Bogenliausen  bei  Miiuchen." 


438  THE    ELECTKICAL    STATE    OF    THE    AIE 

attracted  hj  a  negative  charge.  It  is  not  easy  to  charge 
the  jar  exactly  to  the  same  potential. 

To  obtain  accurate  quantitative  results  from  exami- 
nations of  the  electrical  condition  of  the  air  requires  some 
practice  and  skill. 

The  insulated  cans  are  constructed  so  as  to  run  for 
twenty-four  hours.  It  should  be  remembered  that  the 
proximity  of  houses,  trees,  etc.,  will  influence  the  readings 
of  the  electrometer  very  much  indeed. 

Medical  officers  of  health  might  very  fairly  be  excused 
from  attempting  to  deal  with  a  subject  which  is  confessedly 
a  very  difficult  one,  seeing  that  the  officials  at  the  Kew 
Observatory  are  continually  in  trouble  with  their  at- 
mospheric electrical  apparatus,  were  it  not  that  health 
officers  are  morally,  if  not  legally,  bound  to  neglect  the 
study  of  no  influence  which  is  likely  to  affect  the  public 
health. 

Some  one  has  said  very  truly  that  a  man  must  be  a 
brave  one  indeed  who  ventured  in  the  present  day  to 
attribute  any  morbid  or  incomprehensible  action  to 
electrical  influence,  as  the  whole  subject  of  electricity  has 
suffered  so  much  from  the  hands  of  the  teachers  of  popular 
science.  Just  as  the  old-fashioned  medical  man  ascribes 
all  obscure  affections  to  that  much-abused  viscus,  the  liver, 
so  every  phenomenon  which  could  not  be  readily  explained 
has  in  the  past  been  attributed  to  electricity,  and  its  first 
cousin,  magnetism.  The  observations  made  at  the  Kew 
Observatory  tend  to  show  that  the  atmosphere  always 
contains  free  electricity,  which  is  positive  in  far  the  great 
majority  of  cases  at  a  certain  height  above  the  gTOund 
(at  5  feet  on  flat  ground).  Out  of  10,500  observations 
made  during  the  years  1845-1847,  only  364  showed 
the  presence  of  negative  electricity.  In  damp  or  rainy 
weather  it  is  occasionally  negative.  The  lowest  stratum 
of   air   close   to   the   earth's   surface   generally  furnishes 


THE    ELECTRICAL    STATE    OF    THE    AIR  439 

negative  electricity.  Quetelet,  who  carried  out  a  series 
of  observations  at  the  Observatory  of  Brussels  from  1844 
to  1848,  only  observed  the  electricity  to  be  negative 
twenty-three  times,  and  these  exceptional  indications 
either  preceded  or  followed  rain  and  storms.  Beccaria 
recorded  a  negative  state  of  the  atmosphere  only  six  times 
during  a  period  of  fifteen  years.  It  has  always  been 
accepted  as  an  article  of  belief  that  positive  electricity, 
like  ozone,  is  never  to  be  found  in  a  dweUing-house. 
We  now  know  that  both  can  be  detected  in  rooms, 
although  the  latter  is  soon  used  up,  unless  the  windows 
are  open,  or  some  efficient  system  of  ventilation  exists. 
Sir  William  Thompson,  by  means  of  his  delicate  instru- 
ments, has  shown  that  either  positive  or  negative  electri- 
city may  be  carried  even  through  narrow  passages  from 
one  room  to  another  by  air. 

M.  Palmieri,  of  the  Vesuvian  Observatory,  has  re- 
cently made  some  interesting  experiments  showing  that 
when  steam  is  condensed  by  cold,  negative  electricity  is 
developed ;  but  that  positive  electricity  is  manifested 
vp'hen  evaporation  takes  place. 

Registration  of  Meteorological  Observations. 

There  is  a  gi'eat  variety  of  registers  for  recording  Registratioi 
meteorological  phenomena,  but  they  do  not  teach  the  eye^^^j^g^ 
much,  unless  arranged  in  the  form  of  curves.  Perhaps 
the  most  useful  is  that  represented  at  the  end  of  Ozone 
and  Antozone,  or  the  meteorological  diagram  of  observations 
made  at  the  Kew  Observatory,  which  appears  in  the 
Times  once  a  w^eek. 


SECTION    III 


SANITARY    EXAMINATION 


FOOD 


CHAPTEE    XXXVIII 


THE    PIJEITY    OF    FOOD 


It  will  be  observed  that  the  8tb  Duty  {vide  page  4) 
whicli  especially  relates  to  the  examination  of  food, 
simply  imposes  on  the  Medical  Officer  of  Health  the 
obligation,  when  required,  of  deKvering  an  opinion  as 
to  whether  any  given  sample  of  either  of  the  three 
great  solid  necessaries  of  life,  namely,  flour,  meat,  and 
vegetables,  is  or  is  not  injurious  to  health.  On  the 
wholesomeness  of  these  substances  the  health  of  the 
great  mass  of  the  public  to  a  large  extent  depends. 

That  teas  are  faced,  to  give  them  a  bloom,  with 
ferrocyanide  of  iron,  considered  by  the  majority  of 
physicians  to  be  deleterious  to  health ;  that  ales  are 
salted  to  make  customers  more  thirsty ;  that  nearly 
every  sherry  is  plastered ;  that  fusel  oil  is  a  frequent 
accompaniment  of  raw  spirits ;  that  sugar  often  contains 
iron  and  sand ;  that  preserved  vegetables  are  frequently 
coloured  with  copper ;  that  lemonades,  beer,  and  porter 
not  uncommonly  contain  lead ;  that  tea  is  weighted  with 
iron,  and  weakened  with  leaves  of  the  thorn  and  other 
plants ;  that  butter  is  sometimes  made  without  cream ; 
that  coffee  is  adulterated  with  rotten  figs,  which  have 
been   roasted   and   ground   to   powder  ;^    that  ports   are 

^  One   sample   of  coffee   recently   examined  in   the   Paris   Municipal 
Laboratory  was   reported   to   contain   red  earth,    flour,   cofi'ee   grounds, 


444  THE   PURITY    OF   FOOD 

manufactured  at  chemical  works : — are  all  facts  which 
are  now  pretty  well  known  to  the  public,  who  have  the 
remedy  in  their  own  hands,  in  the  shape  of  "  The  Sale  of 
Food  and  Drugs  Act"  of  1875,  and  as  amended  in 
1879. 

As  none  of  these  articles  are  necessaries  of  life,  the 
detection  of  their  fraudulent  manipulation  does  not  fall 
within  the  scope  of  the  duties  of  the  Medical  Officer  of 
Health  as  laid  down  by  law,  and  will  not  therefore  be 
dealt  with  in  this  work. 

It  is  as  difficult  to  propound  any  exact  definitions  of 
wholesome  and  unwholesome  food,  as  to  draw  a  boundary 
line  between  the  animal  and  vegetable  kingdoms,  for  there 
is  an  almost  insensible  gradation  of  one  into  the  other. 
Game,  venison,  and  mutton  which  have  been  hung  for  a 
short  time  are  more  digestible  than  if  eaten  fresh.  Cheese 
which  is  of  a  certain  age  is  more  palatable  than  when  it 
is  very  new.  Chinamen  are  said  to  swallow  stale  in 
preference  to  fresh  eggs.  The  Esquimaux  eat  putrid 
blubber.  Oysters  acquire  a  flavour  when  stale,  which 
renders  them  more  appetizing  to  the  gourmand  than 
when  fresh.  But  as  a  general  rule,  to  which  there  are 
some  few  exceptions,  it  may  be  said  that  freshness  is 
allied  to  wholesomeness,  and  staleness  to  unwholesome- 
ness  in  the  matter  of  food. 

AUied  to  the  great  question  as  to  the  purity  of  food 
lies  the  extensive  one : — (1)  as  to  the  proportion  which 
the  amount  of  flesh -forming,  heat -giving,  and  saline 
ingredients  bear  to  the  health  of  individuals  of  different 
ages  and  circumstances  of  life ;  (2)  as  to  the  amount 
necessary  to  maintain  healthy  life  in  our  prisons,  lunatic 
asylums,  pauper  schools,  workhouses,  and  reformatories. 

caramel,  talc,  plumbago,  vermicelli,  semolina  powder,  bean  dust,  carrots, 
bread  crusts,  acorns,  sawdust,  red  oclire,  brick  dust,  ashes,  mahogany 
shavings,  vegetable  earth,  and  sand. 


THE    PUEITY    OF    FOOD  445 

It  appears  that  in  some  of  tlie  Cambridge  Sanitary 
Science  Examinations  questions  on  these  subjects  have 
been  introduced.  As  the  Medical  Officer  of  Health  is 
inconsistently  {vide  1st  Duty,  page  4)  excluded  from  the 
medical  supervision  of  Public  Institutions,  even  from  the 
Hospital  for  Infectious  Diseases,  this  branch  of  the  food 
question  must  be  omitted  from  this  handbook. 


CHAPTER    XXXIX 

INSPECTION   AND    EXAMINATION    OF    ANY    ANIMAL 
INTENDED    FOR    THE    FOOD    OF    MAN 

Study  of  the  The  possession  by  the.  Medical  Officer  of  Health  of  some 
animals,  knowledge  of  the  diseases  of  animals  is  of  great  value  to 
him,  not  only  in  guiding  him  in  the  formation  of  an 
opinion  which  may  be  required  of  him  as  to  the  whole- 
someness  of  their  flesh  for  food,  but  as  opening  out  to 
him  a  field  wdiich  has  hitherto  been  barely  worked,  as 
to  the  relation  between  certain  diseases  of  man  and  those 
of  his  humble  associates.  The  writings  of  Gamgee, 
Fleming,  and  Wilhams  will  be  found  to  be  of  great 
service  to  those  who  are  engaged  in  the  study  of 
veterinary  medicine.  It  is  wise  to  take  every  oppor- 
tunity that  offers  of  making  oneself  conversant  with  the 
diseases  of  animals,  and  of  encouraging  the  performance 
of  post-mortems  in  all  doubtful  cases.  During  my 
studies,  cases  of  cattle  plague,  pleuro-pneumonia,  typhoid 
fever  in  pigs,  foot-and-mouth  disease,  splenic  apoplexy 
and  other  forms  of  anthrax,  glanders,  fever  of  a  puerperal 
description  following  parturition,  ringworm,  hydrophobia, 
distemper,  etc.  etc.,  have  come  under  my  notice.  It  is 
only  for  the  Medical  Officer  of  Health  to  look  out  for 
samples  of  these  maladies,  and  many  chances  wHl  present 
themselves  in  rural  districts  of  making  a  practical  ac- 
quaintance with  them. 

The  diseases  of  live  stock  in  their  relation  to  public 


EXAMINATION  OF  ANY  ANIMAL  INTENDED  FOR  FOOD    447 

supplies  of  meat  may  be  summarized  in  the  following 
manner  :^ — 

1.  Contagious  Fevers. 

2.  Anthracic  and  Anthracoid  Diseases. 

3.  Parasitic  Diseases. 

1.  Contagious  Fevees. 

(a)  Epidemic  pleuro- pneumonia,  or  lung  fever, 
principally  found  in  horned  cattle. 

(h)  Aphthous  fever,  or  foot-and-mouth  disease 
(murrain),  which  affects  horned  cattle,  sheep, 
and  swine. 

(c)  Smallpox  of  sheep  (Variola  ovina). 

(d)  Cattle    plague     (Einderpest,     Typhus     Con 

tagiosus). 

2.  Antheacic    and    Anthracoid    Diseases  =  milz 

BEAND  of  German  pathologists. 

They  prevail  as  epidemic   diseases  localized   in  par- 
ticular sections  of  the  country,  and  are  known  as — 

(a)  Splenic  fever,  or  apoplexy  of  horned  cattle 

and  sheep. 
(h)  The  braxy  of  sheep  =  splenic  apoplexy. 

(c)  The  black  quarter,  or   black  leg,  of  horned 

cattle  and  sheep. 

(d)  The  gloss  anthrax,  or   tongue  carbuncle,  of 

almost  exclusively  horned  cattle. 

(e)  The  forms  of  anthrax  which  affect  the  mouth, 

pharynx,  and  neck  in  swine. 
(/)  The  apoplexy  of  swine  and   their   so-called 

blue-sickness,  or  hog-cholera. 
(g)  The  parturition  fever  of  cows,  etc. 

^   Vide  Public  Health  Report  of  Medical  Officer  of  Privy  Council.     No. 
5.     1862. 


448    EXAMINATION  OF  ANY  ANIMAL  INTENDED  FOE  FOOD 

3.  The  Paeasitic  Diseases,  such  as — 

"  Measles "  of  the  pig ;  the  various,  chiefly 
visceral,  diseases  of  stock  which  depend  on 
larvae  of  the  taenia  marginata  and  taenia 
echinococcus  ;  the  "  rot "  of  sheep  ;  the 
lung  disease  in  calves  and  lambs ;  and  the 
easily  overlooked,  but  highly  important, 
disease  of  swine,  which  consists  of  an  in- 
festation of  their  muscular  system  by  the 
minute  immature  forms  of  the  "  trichina." 


CHAPTEE    XL 

INSPECTION  AND  EXAMINATION  OF  CAKCASES  OF  ANIMALS, 
MEAT  AND  FLESH  EXPOSED  FOR  SALE,  OR  DEPOSITED 
FOR  THE  PURPOSE  OF  SALE,  OR  OF  PREPARATION  FOR 
SALE,  AND  INTENDED  FOR  THE  FOOD  OF  MAN 

This  section  of  the  duties  of  the  Medical  Officer  of  Health 
as  to  food  would  seem  to  rank  first  in  importance,  and  to 
comprehend  a  consideration  of  the  suitability  not  only  of 
the  beef,  mutton,  lamb,  veal,  and  pork  that  may  be  pre- 
pared for  the  food  of  the  whole  community,  but  the 
wholesomeness  of  those  kinds  of  animal  food  which  are 
employed  by  certain  special  classes  of  the  people,  such  as 
game,  poultry,  and  fish. 

Mr.  John  Gamgee  expresses  his  belief  that  as  much 
as  one-fifth  part  of  the  common  meat  of  the  country — 
beef,  veal,  mutton,  lamb,  and  pork — comes  from  animals 
which  are  considerably  diseased. 

Mr.  Simon,  in  the  report  already  alluded  to,  gives  the 
following  digest  of  Mr.  J.  Gamgee's  investigations,  made 
at  the  request  of  the  Government : — 

"  Horned  cattle  affected  with  pleuro-pneumonia  are 
much  oftener  than  not  slaughtered  on  account  of  the 
disease,  and  when  slaughtered  are  commonly  (except  their 
lungs)  eaten,  and  this  even  though  the  lung  disease  has 
made  such  progress  as  notably  to  taint  the  carcase ;  that 
animals  affected  with  foot-and-mouth  disease  are  not  often 

2  G 


450  INSPECTION    AND    EXAMINATION    OF    MEAT 

slaughtered  on  account  of  it,  but,  if  slaughtered,  are 
uniformly  eaten ;  that  animals  affected  with  anthracic 
and  anthracoid  diseases,  especially  swine  and  horned 
cattle,  are  (except  their  gangrenous  parts)  very  extensively 
eaten ;  that  the  presence  of  parasites  in  the  flesh  of  an 
animal  never  influences  the  owner  against  selling  it  for 
food ;  that  carcases  too  obviously  ill-conditioned  for  ex- 
posure in  the  butcher's  shop  are  abundantly  sent  to  the 
sausage-makers,  or  sometimes  pickled  and  dried ;  that 
specially  diseased  organs  will  often,  perhaps  commonly,  be 
thrown  aside,  but  that  some  sausage-makers  will  utilize 
even  the  most  diseased  organs  which  can  be  furnished 
them ;  that  the  principal  alternative,  on  a  large  scale,  to 
the  above  -  described  human  consumption  of  diseased 
carcases  is  that,  in  connection  with  some  slaughtering 
establishments,  swine  (destined  themselves  presently  to 
become  human  food)  are  habitually  fed  on  the  offal  and 
scavenage  of  the  shambles,  and  devour,  often  raw  and 
with  other  abominable  fllth,  such  diseased  orsfans  as  are 
below  the  sausage-maker's  standard  of  usefulness." 

Characters  of  Good  and  Bad  Meat. 

The  appearance  and  odour  of  good  fresh  meat  is  known 
to  most  people.  The  Medical  Officer  of  Health,  however, 
should  possess  a  critical  knowledge  which  may  enable  him 
to  guide  a  sanitary  authority  in  cases  of  doubt,  where, 
from  disease  or  otherwise,  the  ordinary  characters  of  good 
meat  are  partially  absent,  or  attended  by  some  irregularity. 
The  muscle  of  young  animals  is  pale  and  moist,  and  that 
of  old  ones  is  dark-coloured.  A  deep  purple  tint  is 
suggestive  that  the  animal  has  not  been  slaughtered,  or 
has  been  slaughtered  in  a  dying  state,  or  has  suffered 
from  some  fever. 

The  characters  of  good  and  bad  meat  are  generally 
thus  laid  down. 


INTENDED    FOR    THE    FOOD    OF    MAN  451 

Good — Firm  and  elastic  to  toiicli ;  marbled  appear-  Good. 
ance ;  should  scarcely  moisten  the  finger ;  no  odour, 
beyond  tliat  pecuKar  to  fresh  meat,  which  every  one 
knows ;  upon  standing,  a  small  quantity  of  a  reddish 
juice  oozes  from  it,  and  it  becomes  dry  upon  the  surface ; 
marrow  of  bones  is  of  a  light  red  colour. 

Bad. — Wet ;  sodden  ;  flabby  ;  purulent  fluid  in  inter-  Bad. 
muscular   cellular   tissue ;    fat   resembling  jelly,    or   wet 
parchment,  or  exhibiting  haemorrhagic  spots ;    sickly  or 
putrefactive  odour ;  on  standing  it  becomes  wet ;  marrow 
of  bones  of  a  brownish  colour,  sometimes  with  black  spots. 

It  should  be  remembered  that  meat  may  not  reach 
the  standard  of  good  meat  and  yet  be  perfectly  wholesome, 
so  difficult  is  it  to  lay  down  rules  to  which  there  shall  be 
no  exceptions  ;  for  example,  a  perfectly  fresh  leg  of  mutton 
is  tough  and  by  no  means  pleasant  eating.  If  kept  until 
it  begins  to  lose  some  of  the  characters  above  enumerated 
as  indicating  good  meat,  which  may  be  a  long  time  if  the 
weather  be  cold,  and  especially  if  the  air  be  dry,  it  is 
tender  and  digestible.  If  an  opinion  cannot  readily  be 
formed,  the  lungs  and  their  coverings,  the  liver,  brain,  and 
other  viscera  of  the  suspected  animal  should  be  carefully 
examined.  Signs  of  inflammation  are  to  be  found  in  the 
lungs  and  pleura ;  hydatids  may  be  present  in  the  brain 
and  liver.  The  condition  of  the  mouth,  stomach,  and 
intestines  should  be  examined,  if  there  is  a  probability  of 
rinderpest,  and  that  of  the  feet,  teats,  and  mouth  when 
there  is  a  suspicion  of  aphthous  fever. 

There  never  can  be  any  doubt  as  to  the  propriety  of 
condemning  meat  that  has  become  putrid,  for  it  produces 
violent  gastro -intestinal  disturbance,  until  the  offending 
matter  has  been  removed  either  by  vomiting  or  purging. 
Numerous  cases  are  to  be  found  in  medical  records  of 
fatal  results  following  the  ingestion  of  animal  substances 
in  a  state   of  advanced  putrefaction.      Certain  kinds  of 


452  INSPECTION    AND    EXAMINATION    OF    MEAT 

meat  whicli  will  not  "  keep  "  well  readily  undergo  some 
change  which  results  in  the  formation  of  a  poison  that 
will  produce  violent  gastro-intestinal  disturbance.  Veal 
in  the  form  of  a  pie,  if  placed  aside  in  a  warm  cupboard, 
will  often  when  consumed  produce  such  unpleasant  effects. 
If,  on  cutting  a  cold  veal  pie,  the  jelly  is  found  to  be  in  a 
fluid  state  it  is  wise  to  avoid  it. 

Certain  damaged  meat,  such  as  mouldy  veal,  musty 
bacon,  decaying  mutton,  sausages,  bacon,^  pork  pies,  brawn,^ 
potted  meats  ^  in  a  state  of  incipient  putrefaction,  cheese, 
etc.,  have  acted  like  irritant  poisons,  producing  great 
nervous  depression  and  collapse.  It  has  been  supposed 
that  these  defects  are  owing  to  the  formation  of  a  rancid 
fatty  acid,  or  a  poisonous  organic  alkaloid,  or  to  the 
development  of  a  fungus,  termed  Sarcina  hotulina. 

The  smell,  appearance  to  the  naked  eye  and  under  the 
microscope,  will  readily  reveal  the  condition  of  meat  in 
this  state. 

The  detection  of  decomposition  in  sausages  is  found  to 
be  more  difficult.  It  has  been  recommended  to  mix  the 
sausage  with  water,  to  boil  and  add  freshly-prepared  lime- 
water,  when  an  offensive  odour  will  be  evolved  if  the 
sausages  are  unwholesome.  The  existence  of  an  acid 
reaction  to  litmus  j^aper,  an  unpleasant  odour  and  a 
nauseous  taste,  are  signs  of  their  unfitness  for  human 
food. 
Acid,  aika-  Beactiou  with  Litmus  Paper. — Good  meat  is  acid,  and 
neutral?  therefore  turns  blue  litmus  paper  to  a  red  colour.  Bad 
meat  is  alkaline  or  neutral,  and  accordingly  changes  red 
litmus  paper  to  a  blue  colour,  or  neither  the  blue  nor  red 
litmus  paper  are  altered  by  it. 

Degree  of  Resistance  of  various  parts  when  pressed. — 


Degree  of 
Resistance 


1  Medical  Times,  March  7,  1845.     • 

2  British  Medical  Journal,  May  10  and  17,  1873. 
^  Medical  Times  and  Gazette,  August  5,  1854. 


INTENDED    FOR   THE    FOOD    OF    MAN  453 

Plunge  a  long  clean  knife  into  the  flesh.  In  good  meat 
the  resistance  is  uniform ;  in  bad  meat  some  parts  are 
softer  than  others. 

Smell  of  Meat. — The  knife  after  removal  should  besmeii. 
smelt.  If  the  meat  is  chopped  up  into  small  portions 
and  some  hot  water  thrown  on  it,  its  odour  can  be  readily 
determined.  An  unpleasant  odour  indicates  disease,  or 
incipient  putrefactive  changes.  Meat  which  has  a  smell 
of  physic  is  generally  condemned. 

Loss  of  Weight  in  drying  at  212°  F. — Good  meat,  if  Amount  of 
dried  for  some  hours  on  a  water  bath,  will  not  lose  more 
than  70  to  74  per  cent  of  its  weight. 

Bad  meat  will  often  lose  80  per  cent.  {Vide  Pre- 
cautions to  be  adopted  in  estimating  loss  of  moisture,  on 
page  496). 

If  there  is  any  reason  to  think  that  an  animal,  the 
meat  of  which  is  siib  Judice,  has  been  drugged,  although 
the  appearance  and  smell  of  the  meat  are  unobjectionable, 
it  is  sometimes  necessary  to  cook  and  taste  it,  for  the  fat 
of  a  drugged  animal,  after  cooking,  has  often  a  peculiar 
bitter  taste.  Such  drugged  meat  sometimes  creates  illness. 
As  to  the  meat  of  an  animal  respecting  which  there  is 
any  suspicion  of  poisoning  by  arsenic,  antimony,  or 
strychnine,  a  rough  and  ready  test  is  the  physiological 
one  of  giving  a  portion  of  the  meat  to  a  cat  or  dog,  or  to 
the  butcher  who  is  selling  it,  and  to  note  if  symptoms  of 
poisoning  are  produced,  and  if  so,  the  exact  nature  of  the 
symptoms,  for  each  of  those  poisons  produces  characteristic 
effects,  which  are  fully  laid  down  in  all  books  on  toxi- 
cology. Such  cases  of  poisoning  of  meat  are  rare.  Mr. 
Gamgee  reports  one^  in  which  an  animal  had  been  ex- 
cessively drugged  with  tartar  emetic  (about  gij.)  Of  321 
persons  who  ate  of  the  flesh,  107   suffered  from  violent 

1   Fiftli  Report  of  Medical  Officer  of  Privy  Council,  1862. 


454 


INSPECTION    AND    EXAMINATION    OF    MEAT 


gastro-intestinal  disturbance,  one  case  proving  fatal. 
Antimony  was  chemically  found,  botli  in  the  flesh  of  the 
ox  and  in  the  interior  of  the  individual  who  died.  Doses 
of  the  flesh,  which  were  given  experimentally  to  animals, 
produced  signs  of  poisoning. 

The  following  analyses  of  Letheby  and  Eanke  may 
prove  interestmg : — 


Beef. 

Veal. 

Mutton. 

Fat 
Pork. 

Roast  Meat. 

No  dripping 

lost. 

Lean. 

Fat. 

Lean. 

Fat. 

Nitrogenous 

matter     . 

19-3 

14-8 

16-3 

18-3 

12-4 

9-8 

27-6 

Fat     . 

3-6 

29-8 

15-8 

4-9 

31-1 

48-9 

15-45 

Saline  matter 

5-1 

4-4 

4-7 

4-8 

3-5 

2-3 

2-95 

Water 

72-0 

51-0 

63-0 

72-0 

53-0 

39-0 

54-00 

Tlie  Prevalent  Diseases  of  Stock  in  relation  to  the  supply  of 
Meat  for  Kuman  Food. 

Theoretically,  the  meat  of  the  healthiest  animals  that 
have  been  slaughtered  is  alone  fit  for  the  food  of  man. 

Practically,  meat  that  has  been  obtained  from  sickly 
and  even  diseased  animals  has  been  eaten  with  impunity, 
and  no  proof  has  been  afforded  that  such  meat  has 
always  been  injurious  to  health,  although  abundant 
evidence  is  on  record  which  shows  the  occasional  evil 
results  of  its  consumption. 

To  understand  this  fact,  which  has  been  deemed 
incomprehensible,  it  is  necessary  to  make  a  distinction 
between  the  diseases  from  which  our  stock  suffers,  and 
between  the  meat  furnished  by  animals  at  different  stages 
of  these  diseases. 


Pleuro- 
pneumonia. 


1.   Contagious  Fevers. 

Hie    Epidemic    Pleuro- Pneumonia    of    Cattle    is     an 
infectious    disease,   the    poison    of    which    is    eliminated 


INTENDED    FOR    THE    FOOD    OF   MAN  455 

through  the  hmgs.  The  appearance  of  the  lungs  and 
pleura  is  similar  to  that  presented  in  a  post-mortem  of 
pleuro-pneumonia  in  the  human  subject,  with  which  every 
medical  man  is  acquainted.  The  divergence  of  opinion 
that  has  prevailed  in  the  medical  profession  as  to  what  is 
and  what  is  not  wholesome  meat,  has  expressed  itself 
chiefly  in  connection  with  the  flesh  of  pleuro-pneumonic 
cattle.  Some  would  condemn  meat  that  exhibited 
evidence  of  perverted  nutrition  far  short  indeed  of  actual 
disease,  whilst  others  would  allow  unsound  meat  to  be 
eaten  unless  it  exhibited  such  signs  of  disease  as  to  excite 
disgust  in  the  consumer.  These  are  the  two  extremes  of 
opinion,  and  both  parties  have  much  to  urge  in  support 
of  their  opposite  views.  These  unfortunate  differences 
have  led  to  great  variations  in  practice,  meat  in  precisely 
the  same  condition  being  confiscated  in  one  part  of 
London,  for  example,  wliich  is  permitted  to  be  eaten  in 
another  part.  They  have  led  also  cattle-dealers,  farriers, 
and  other  interested  individuals,  to  rebel  against  the 
opinion  of  scientific  medical  officers  of  health,  of  which 
we  had  an  instance  some  years  ago  in  Dublin. 

In  September  1877  the  Public  Health  Committee 
of  the  Corporation  of  this  city  addressed  a  circular 
letter,  at  the  suggestion  of  the  Medical  Officer  of 
Health,  Dr.  Cameron,  to  a  great  number  of  medical 
men  in  the  United  Kingdom,  including  medical  officers 
of  health,  and  to  veterinarians,  containing  the  following 
queries : — 

1.  Do  you   consider  the  flesh  of  oxen  killed  whilst 

suffering  from  contagious  pleuro-pneumonia  fit 
for  food  for  man  ? 

2.  If  you  consider  that  such  flesh  may  be  used  under 

certain  circumstances,  please  state  whether  or  not 
it  is  fit  for  food  in  the  second  stage  of  the  disease, 
in  which  the  lungs  are  usually  much  increased  in 


456  INSPECTION    AND    EXAMINATION    OF    MEAT 

size,  partially  hepatized,  and  sometimes  more  or 
less  infiltrated  with  pus  ? 

290  replied  that  under  no  circumstances  should 
pleuro-pneumonic  beef  be  used  as  food  by  man;  45 
stated  that  it  might  be  used  in  the  early  stage,  but,  with 
two  exceptions,  they  believed  it  to  be  unwholesome  in 
the  advanced  stages  of  the  disease.^ 

It  should  be  recorded  that  Loiset  affirms^  that  during 
nineteen  years  18,000  oxen  affected  with  pleuro-pneu- 
monia  were  killed  and  used  as  food  by  the  150,000 
inhabitants  of  Lille,  or  nearly  1000  carcases  every  year, 
without  any  apparent  injury  to  them. 

Other  authorities  have  made  similar  observations  as  to 
its  innocuous  character.^ 

My  own  opinion  is  that,  until  it  can  be  shown  that 
the  meat  of  animals  in  the  congestive  and  inflammatory 
stages  of  the  disease  is  deleterious  to  health,  a  Medical 
Officer  of  Health  has  no  right  to  have  it  destroyed.  I 
could  not,  however,  sanction  the  employment  of  the  meat 
of  an  animal  that  had  reached  the  suppurative  and 
advanced  stages  of  the  disease. 
Foot-and-  Foot  -  cmd  -  Moivtli    Diseccsc. — Although     this     specific 

Disease.  cruptivc  fcvcr,  wliicli  ruus  a  definite  course  and  is 
accompanied  by  eruptions  in  the  mouth,  on  the  teats, 
and  on  the  feet,  is  rarely  fatal,  it  has  created  greater 
ravages,  and  has  caused  a  more  heavy  loss  than  cattle 
plague.  Mr.  Vacher,  who  has  made  a  special  study  of  the 
diseases  of  animals,  says  of  it:*  "The  eruption  consists 
of  blisters  which  leave,  if  they  break,  bare  red  spots  like 
small  ulcers.  After  they  dry  up,  crusts  form.  Bound 
the  feet  the  contents  of  the  blisters  burrow  between  the  soft 

^  ' '  Report  on  the  Use  of  Flesh  of  Animals  affected  with  Contagious 
Pleuro-Pueumonia  as  Food  for  Man,"  by  Dr.  C.  A.  Cameron. 

^  Reynal's  Trait6  de  la  Police  Sanitaire. 

s  "Report  to  Board  of  Trade,"  by  Dr.  Greenhow,  1857. 

*  Sanitary  Eecord,  October  15,  1885. 


INTENDED    FOR   THE    FOOD    OF    IIAN  457 

parts  and  hoof  wliicli  is  sometimes  shed.  Occasionally 
(especially  in  sheep)  no  regular  blisters  occur  on  the  feet, 
but  the  skin  becomes  red  and  swollen,  and  exudes  a 
thick,  gummy  fluid.  The  head,  feet  and  udder  should  be 
seized.  When  the  eruption  has  extended  into  the  in- 
testines, as  is  not  infrequent  with  calves  suckled  from  a 
diseased  udder,  or  when  there  is  much  inflammation  and 
abscesses,  the  carcase  should  be  condemned."  The  loss  of 
milk,  the  abortion  of  cows  in  calf,  the  loss  of  time  and 
produce,  interferes  greatly  with  the  meat -producing 
powers  of  the  country. 

One  of  the  witnesses  before  the  Select  Committee  of  the 
House  of  Commons  in  1 8  7  3  stated  that  in  1 8  7  2  the  country 
lost  £12,000,000  from  foot-and-mouth  disease  alone. 

There  is  no  evidence  on  record  to  show  that  the  flesh 
of  cattle  and  sheep  affected  with  this  disease  has  injured 
health,  although  it  is  generally  pale,  flabby,  and  unduly 
moist.  It  is  an  undoubted  fact,  however,  that  the  milk 
of  these  animals  has  produced  "sore"  or  "festered"  mouths, 
especially  amongst  children  {vide  page  539). 

Smallpox  of  81u&p. — Mr.  Vacher  states  that  the  smaiipox  of 
eruption  at  first  resembles  flea-bites  which  become  solid 
pimples,  containing  a  clear  fluid  which  changes  into  pus, 
and  that  the  wool  comes  off  readily.  The  flesh  of 
animals  thus  affected  has  an  unpleasant  smell,  and  does 
not  possess  some  other  of  the  characters  of  good  meat, 
being  soft,  pale,  and  dropsical.  It  produces,  if  eaten, 
sickness,  diarrhoea,  and  febrile  symptoms. 

CattU    Plaque     (Einderpest). — The     flesh     does     notcattie 

1  .1  .  Ill  •        1  •       T  1         Plague  or 

exhibit  any  unhealthy  appearances  m  this  disease,  unless  Rinderpest, 
it  is  in  an  advanced  stasje,  when  it  is  dark  and  crackles 
from  the  presence  of  air.  In  addition  to  indications  of 
catarrh  in  the  air  passages,  there  are  signs  of  inflamma- 
tion and  ulceration  in  the  intestinal  canal.  The  patches  of 
ulceration  reminded  me,  in  some  post-mortems  made  under 


458  INSPECTION    AND    EXAMINATION    OF    MEAT 

my  superintendence,  of  the  ulcers  in  enteric  fever.  Mr. 
Vacher  refers  to  the  existence  of  an  eruption  on  the  back, 
loins,  and  inside  of  the  thighs,  and  in  the  cow  on  the 
udder.  When  this  disease  ravaged  Italy  in  1711  the 
Government  of  Venice  consulted  the  Faculty  of  Padua  as 
to  whether  such  flesh  was  unwholesome.  The  decision 
arrived  at  was  that  it  was  unattended  with  danger.  In 
1714,  when  the  disease  prevailed,  no  evil  consequences 
were  observed.  In  1775,  when  the  plague  raged  in  the 
southern  provinces  of  France,  the  flesh  of  diseased  animals 
was  consumed  by  three-fourths  of  the  inhabitants,  and  no 
instance  of  inconvenience  was  recorded  (Fleming).  This 
author  also  informs  us  that  the  same  freedom  from  any 
injurious  effects  was  noticed  at  Hong-Kong,  in  China,  in 
1860.  During  the  invasion  by  rinderpest  of  this  country, 
in  1865-67,  there  can  be  no  question  but  that  a  vast 
quantity  of  animals  suffering  from  this  disease  were 
consumed  as  food,  and  loe,  as  medical  men,  are  unable  to 
prove  that  any  great  injury  resulted  to  the  public.  The 
meat  thus  employed  was  doubtless  that  of  animals  in  the 
early  stage  of  the  disease.  If  such  meat  is  consumed  the 
greatest  precautions  should  be  taken  as  to  thorough 
cooking.  It  is  a  matter  of  doubt  whether  the  flesh  of  an 
animal  in  the  advanced  stages  can  be  eaten  with  safety. 

2.  Anthracic  and  Anthracoid  Diseases,  etc. 

Splenic  S^pUnic  FevcT  or  Apoplexy. — The  memoranda  of  Mr. 

Apoplexy.  Vaclicr  respecting  this  disease,  which  sometimes  assumes 
the  form  of  apoplexy,  are  : — "  Meat  dark,  often  dropsical ; 
whole  carcase  is  bile  stained;  liver  generally  enlarged  and 
softened  ;  lungs  generally  inflamed  ;  increase  of  weight  of 
spleen,  with  rounded  edges,  in  an  ox  from  3  lbs.  to  7  lbs. 
or  10  lbs.,  and  in  sheep  from  2  or  3  oz.  to  5  or  6  oz." 
Great  differences  of  opinion  have  prevailed  as  to  whether 
animals   thus   diseased   should  be  used  as  human  food. 


INTENDED    FOE    THE    FOOD    OF    MAN  459 

Large  quantities  of  this  meat  liave  been  eaten,  and  with 
apparently  no  injurious  effects ;  but  so  many  disastrous 
occurrences  have  followed  its  employment  as  to  warrant 
the  Medical  Officer  of  Health  in  condemning  such  meat. 
The  poison  of  this  diseased  meat  resembles  some  others 
in  acting  with  greater  virulency  when  inserted  sub- 
cutaneously  than  when  taken  into  the  stomach.  A 
butcher  cuts  his  hand  in  dressing  an  animal  that  has 
suffered  from  this  disease,  and  rapidly  dies  of  septicsemia. 
A  carrier  was  packing  some  of  this  diseased  meat 
for  the  London  market,  and  a  splinter  of  bone  entered 
his  hand.  Phlegmonous  erysipelas,  which  ended  speedily 
in  blood-poisoning,  terminated  his  life  in  a  few  hours. 
A  man  was  engaged  during  a  dark  night  in  resur- 
rectionizing  a  diseased  animal  that  had  been  buried.  He 
hoisted  some  of  the  meat  in  a  sack  over  his  back, 
which  was  covered  by  his  shirt  alone.  In  some  way  or 
other  the  juices  of  the  meat  passed  through  the  sack  and 
shirt,  and  came  into  contact  with  the  skin  of  the  back, 
on  which  there  was  probably  some  abrasion.  Erysipelatous 
inflammation  of  the  skin,  attended  with  intense  depression 
of  the  vital  powers,  rapidly  set  in,  and  the  man  expired. 

The  dust  from  the  wool  and  hair  of  animals  that  have 
died  of  this  disease  is  often  inhaled  by  the  sorters,  packers, 
and  cleaners  of  the  same,  and  becomes  the  medium  for  the 
conveyance  of  the  poison.  " Woolsorters'  disease"  has 
been  proved  to  be  due  to  a  specific  organism,  named  the 
bacillus  anthracis,  which  is  abundant  in  the  blood  and 
tissues  of  the  diseased. 

M.  Pasteur  has  so  attenuated  by  cultivation  the  virus 
of  splenic  fever  as  to  have  been  able  to  produce  a  benign 
and  mitigated  kind,  protective  against  the  deadly  form. 
He  believes  that  these  bacilli  are  conveyed  by  earthworms 
from  a  buried  carcase  to  the  surface,  thus  propagating  it 
to  animals  who  are  grazing  above. 


460  INSPECTION   AND    EXAMINATION    OF    MEAT 

I  cannot  think  that  meat  containing  such  a  deadly 
poison  should  ever  be  sold  to  the  public. 
Anthrax,  Antkrax,  Mack  Quarter,  Gloss  Anthrax. — The  literature 

Elack  ^  ' 

Quarter,  and  of  the  past  tceuis  with  cxamples  of  the  poisonous  nature 
<jioss  Qf  ^]^Q  flesh  of  animals  that  have  suffered  from  anthracic 

Autlirax. 

diseases,  although  many  instances  can  be  adduced,  showing 
the  escape  of  people  who  have  been  imprudent  enough  to 
risk  their  health  and  lives  in  consuming  it.-^  The  malig- 
nant pustule  of  the  human  subject  is  produced  by  these 
anthracic  diseases  of  stock,  which  are  included  by  the 
French  under  the  head  of  "  Charbon,"  thus  named  because 
the  regions  of  the  body  where  the  disease  is  localized  are 
coloured  black.  In  this  country  the  development  of 
carbuncles,  boils,  and  other  forms  of  blood-poisoning  has 
been  attributed  to  the  use  of  meat  from  animals  affected 
with  anthracic  diseases.  All  such  meat  should  be  con- 
demned. The  use  of  the  milk  of  animals  suffering  from 
anthracic  diseases  should  be  interdicted. 
TheBraxy  The  Brojxy  of  Sheep,  which  kills  50  per  cent  of  the 

young  sheep  of  Scotland,^  is  readily  recognized  by  the 
shepherds  by  a  short  staggering  gait,  bloodshot  eyes,  rapid 
breathing,  fever,  scanty  secretions.  The  braxy  mutton  is 
preferred  to  salt  mutton  by  the  hardy  Highland  shepherds, 
but  it  is  not,  as  a  rule,  cooked  and  eaten  until  it  has 
been  steeped  in  brine  for  two  months,  and  has  been  sus- 
pended for  some  time  from  the  kitchen  roof  Dr.  Letheby 
writes  :^  "  Every  now  and  then,  however,  when  perhaps 
the  diseased  parts  have  not  been  entirely  removed,  or 
when  the  salting  has  not  been  sufficiently  prolonged,  or 
the  cooking  has  not  been  thoroughly  effected,  the  most 
serious  consequences  result  from  it,  insomuch  that  many 

^  Vide  Fleming's  Manual  of  VeteriTiary  Sanitary  Science,  vol.  ii.  p. 
195. 

-  Vide  the  Prize  Essay  on  Braxy,  by  Mr.  Cowan  of  Glasgow,  in  Trans- 
actions of  the  Highland  and  Agricultural  Society,  1863. 

^   Vidx  Dr.  Letheby's  Lectures  on  Food. 


of  Sheep. 


INTENDED    FOE    THE    FOOD    OF    MAN  461 

medical  practitioners,  who  are  acquainted  with  the  habits 
of  the  Scotch  shepherds  in  this  respect,  and  have  seen  the 
mischief  occasioned  by  the  meat,  declare  that  braxy  mutton 
is  a  highly  dangerous  food  for  man." 

Parturient  Apoplexy  {Milk  Fever,  Dropping  after  Calving 'P^^rtmient 
or  Lambing). — The  condition  of  the  meat  should  govern  MukFever!^ 
the  Medical  Officer  of  Health  in  the  formation  of  an  opinion 
as  to  whether  the  flesh  of  such  animals  is  or  is  not  fit  for 
human  food.  Mr.  .  Gamgee  writes  •}  "  Notwithstanding 
the  sporadic  nature  of  parturient  apoplexy  in  cattle,  it  is 
marked  by  the  development  of  a  poison  capable  of  inducing 
a  similar  disease  in  other  animals,  of  affecting  the  human 
frame,  and  hence  of  rendering  the  flesh  of  animals  affected 
by  it  unfit  for  human  food."  Professor  Williams  writes  r^ 
"  If  this  assertion  were  correct  the  number  of  the  human 
race  would,  ere  this,  have  been  much  reduced,  for  it  is  a 
well-known  fact  that  the  flesh  of  cows,  slaughtered  whilst 
suffering  from  parturient  apoplexy,  is  a  common  article  of 
diet,  and  that  no  bad  consequences  result  from  it,  provided 
the  animal  has  been  slaughtered  early,  before  the  system 
has  been  empoisoned  by  the  excessive  doses  of  medicines 
which  are  so  generally  prescribed  in  this  malady,  and 
antecedent  to  a  general  vitiation  of  the  animal  solids  and 
fluids  by  the  accumulation  of  effete  materials."  Convictions 
in  such  cases  have  been  obtained.  (  Vide,  for  example,  one 
reported  in  Sanitary  Eecord,  March  2,  1877,  page  144.) 
In  cases  of  accidents  during  parturition,  there  can  be  no 
valid  reason  for  objecting  to  a  carcase  which  presents  the 
characters  of  good  meat. 

Tubercular  Diseases. — Large  quantities  of  meat   that  Tubercuia 
finds  its  way  into  our  markets  has  come  from  animals  ^'^^^^'^^' 
more  or  less  affected  with  pulmonary  or  mesenteric  phthisis. 
This  consumptive  disease  is  named  "pearl  disease,"  and 

^  Our  Domestic  Animals  in  Health  and  Disease. 

2  The  Principles  and  Practice  of  Veterinary  Medicine, 


462  INSPECTION    AND    EXAMINATION    OF    MEAT 

by  cattle-dealers  "  grapes."  The  pearls  are  either  tuber- 
cular caseous  deposits  or  enlarged  glands,  sometimes  con- 
taining pus  or  cheesy  and  at  other  times  gritty  matters. 
In  the  early  stages  of  the  disease  the  meat  does  not  present 
any  of  the  characteristics  of  bad  meat,  and  cannot  be 
rejected,  for  no  proof  exists  that  such  food  has  injured 
health.  If  it  is  eaten,  care  should  be  taken  that  it  is  well 
cooked.  In  the  advanced  stages,  when  the  lungs  are 
riddled  with  cavities  and  the  glands  are  in  a  purulent 
state,  it  should  be  destroyed. 
Hog  Oho-  ■  Typhoid  Fever,  Hog  Cholera,  Scarlet  Fever,  Pig  Typhus, 
Typhns!^!ind '^l^ottcd  Fcver,  Sivinc  Plague. — ^Diarrhoea  and  dys]3n£ea, 
Typhoid  with  cougliiug,  are  the  symptoms  of  an  extremely  infectious 
disease  in  the  pig,  which  may  or  may  not  be  accompanied  by 
a  patchy  or  general  redness  of  the  skin  ("  red  soldier  "),  by 
livid  blotches  ("  blue  disease  "),  or  an  eruption  like  variola 
("  smallpox ").  I  had  an  opportunity  of  studj^g  this 
disease  in  a  part  of  Yorkshire  some  years  ago  when  there 
was  a  gTeat  mortality  from  it. 

The  Privy  Council  of  December  17,  1878  provides  that 
"  the  Typhoid  Fever  of  swine  (otherwise  called  Soldier 
Disease  or  Eed  Disease)  shall  be  deemed  to  be  a  disease 
under  the  Contagious  Diseases  Animals  Act  of  1878  for 
the  purposes  of  slaughter  and  compensation,  and  also  imder 
the  Animals  Order  of  1878,  for  the  purposes  of  movement, 
destruction  of  carcases,  disinfection,  etc."  Mr.  Klein, 
F.E.S.,  has  shown  ^  that  this  disease  is  not  of  the  nature 
of  t}^hoid  fever,  and  may  more  correctly  be  named  in- 
fectious pneumo-enteritis.  Mr.  Yacher  has  pointed  out 
that  "  soldier  disease  "  and  "  red  disease  "  are  not  synonyms 
for  the  so-called  tj^hoid,  but  are  merely  popular  names 
given  to  any  affection  of  swine  accompanied  by  general  or 
patchy  redness  of  the  skin,  such  as  is  seen  in  anthrax 

1  Vide  Seventh  Annual  Eeport  of  Local  Government  Board,  1877-78, 
containing  Supplement  of  Medical  Officer  for  1877. 


INTENDED    FOE    THE    FOOD    OF    MAN  463 

fever,  rubeola  {rougeoU  of  the  French),  erysipelas,  erythema, 
and  other  skin  affections,  as  well  as  asphyxia,  heat  apoplexy, 
and  scalding  from  salt  water  in  sea  voyages. 

Mr.  Yacher's  memoranda  respecting  swine  plague  are  : 
"  The  redness  of  the  skin  extends  through  the  fat,  some- 
times the  patches  are  blue,  or  there  is  an  eruption  like 
smallpox  ;  red  spots  and  ulcers  in  intestines.  There  may 
be  intestinal  ulcers,  and  no  lung  or  skin  affection,  or  vice 
versd  ;  butchers  sometimes  rub  salt  along  edges  of  reddened 
fat.  Edge  so  treated  can  readily  be  removed  with  a  knife. 
Sucking  pigs  die  in  great  numbers  when  sows  are  affected 
with  '  hog  cholera.' "  Convictions  are  obtained  for  the  de- 
struction of  animals  that  have  suffered  from  these  blood 
diseases.-^  The  carcases  exhibit  appearances  so  different 
from  those  of  good  meat  as  readily  to  fall  under  con- 
demnation. It  is  stated  that  whole  families  have  been 
made  seriously  ill  by  eating  the  flesh  of  "  soldier  pigs." 

Accidents,  Fractures,  Wounds. — The  flesh  in  these  cases  Accidents, 
may  generally  be  utilized  as  inferior  meat,  except  in  the 
neighbourhood  of  the  injury.      If  gangrene  has  set  in,  its 
use  should  be  prohibited. 

The  flesh  of  overdriven  animals  has  been  stated  by 
Gamgee  to  have  produced  eczema  of  the  skin,  and  other 
unpleasant  effects. 

Arguments  against  the  Emjjloyment  of  Diseased  Meat. 

The  arguments  that  are  employed  by  those  who  would  Arguments 
perpetrate  such  raids  on  our  meat  markets  as  to  condemn  pioymgnrof 
not   only  all   diseased   meat,    but   even   that    of  animals  ^'^^^^^^ 

1  '^       .    .  .  .'  ,  Meat. 

whose  nutrition  is  temporarily  perverted,  are  : — 

■^  Sanitary  Record,  February  5,  1876,  p.  96  (tj'plioid  fever). 
,,  ,,      January  6,  1877,  p.  12  (scarlatina). 

,,  ,,      August  31,  1877,  p.  145  (scarlatina). 

„  ,,      October  26,  1877,  p.  270  (spotted  fever). 


464  INSPECTION    AND    EXAMINATION    OF    MEAT 

1.  That  cases  of  apparent  poisoning  sometimes  arise  in  a  quite 

indefinable  manner  ;  and  that,  if  such  cases  prove  fatal,  no 
known  poison  can  be  detected  by  the  toxicologist. 
It  is  true  that  cases   of  blood  poisoning  occasionally  occur, 
which  have  equally  been  ascribed  to  the  air  from  drains  and 
cesspools,  or  to  filthy  water. 

2.  That  there  has  been  a  great  increase  of  carbuncular  diseases 

ever  since  1842,  the  year  in  which  the  infectious  blood 
disease  of  cattle,  known  as  pleuro- pneumonia,  was  first 
recognized  in  this  country. 
An  increase  in  this  class  of  disease  occurred  during  the  years 
from  1842  to  1854  ;  but  since  this  latter  year  there  has 
been  a  decline. 

3.  That  Dr.  Livingstone  had  remarked  that  those  African  tribes 

that  fed  on  cattle  which  died  of  pleuro-pneumonia  were 
often  affected  with  malignant  carbuncles. 
If  Dr.  Livingstone  was  correct  as  to  the  nature  of  the  disease 
from  which  the  cattle  suffered,  which  appears  very  doubtful, 
it  would  seem  that  the  meat  was  eaten  in  the  most  advanced 
stages  of  the  disease.  If,  as  is  highly  probable,  the  cattle 
died  of  some  form  of  anthracic  disease,  the  result  that 
followed  is  only  that  which  would  be  expected. 

4.  That  the  Registrar-General  of  Scotland  had  noticed  that,  since 

lung  disease  in  animals  was  introduced  into  Scotland,  there 
had  been  a  gradual  increase  in  the  proportion  of  deaths 
from  carbuncles. 

5.  That   cooking    does   not   necessarily   destroy  the  poisonous 

properties  of  diseased  meat  is  rendered  probable  by  the  ex- 
periment of  Dr.  Davies,  who  successfully  vaccinated  with 
lymph  which  had  been  buried  in  the  middle  of  a  leg  of 
mutton  whilst  roasting. 


Arguments  in  favour  of  the  Emfployment  of  Diseased  Meat. 

Arguments  The  arguments  used  by  the  opposite  section  in  the 
mLTo?°^'  profession,  who  would  not  confiscate  meat  unless  it  was 
Diseased  .  almost  rcpulsive,  are  : — 

Meat 

1.  That  our  animal  food  is  exposed  to  so  high  a  temperature  as 

to  kill  animal  poisons,  and  coagulate  and  render  inert  any 
albuminous  morbid  contagium. 

2.  As  the  venom  of  the  cobra  and  the  rattlesnake  is  rendered 

innocuous  after  exposure  to  the  disinfectant  chemistry  of 


INTENDED    FOE    THE    FOOD    OF    MAN  465 

digestion,  so  tlie  poisons  of  such  diseases  as  smallpox,  etc., 
probably  undergo  similar  destruction. 
"  These  two  protective  influences  do  not,"  as  Mr.  Simon  has 
pointed  out,^  "  cover  the  whole  field  of  danger  : — 
"  (a)  Meat  is  often  only  half  cooked  ;  and, 
"  (b)  Complete  coagulation  of  albumen  may  leave  some 
morbid  poisons  in  operation." 
3.  That  the  diseased  flesh  of  glandered  horses,  of  animals  that 
have  died  of  contagious  disease,  rinderpest, anthracoid  diseases, 
and  even  rabies,  have  been  eaten,  after  being  well  cooked,  with 
impunity. 

We  are,  one  and  all,  aware  tliat  terrible  outbreaks  of 
disease  have  occurred  from  the  use  of  meat  other  than 
that  which  we  are  unanimous  in  condemning.  Here  are 
two  out  of  many  instances  : — 

Prof   Gamgee  has  given  evidence  with   reference  to  severe  and 
a   convict    establishment,    containing    1500    inmates,   in '^^'^^!"®"'®    , 

'  o  '  outbreaks  of 

which  diseased  meat  was  permitted  to  be  used,  out  ofdisease. 
which  number  40   or   50   cases  of  boils  and  carbuncles 
occurred  per  month. 

The  late  Dr.  Letheby's  sausage  case,  of  November 
1860,  was  remarkable.  "A  fore  q[uarter  of  cow  beef  was 
purchased  in  Newgate  market  by  a  sausage  manufacturer 
who  lived  at  Kingsland,  and  who  immediately  converted 
it  into  sausage  meat.  Sixty-six  persons  were  known  to 
have  eaten  that  meat,  of  which  sixty-four  were  attacked 
with  sickness,  diarrhoea,  and  great  prostration  of  the  vital 
powers,  and  one  of  them  died.  Dr.  Letheby  found  that 
the  meat  was  diseased,  and  that  it,  and  it  alone,  had  been 
the  cause  of  the  mischief" 

It  is  extremely  difficult  to  trace  cases  of  illness  to 
the  use  of  diseased  meat,  for  such  does  not  generally  pro- 
duce such  striking  and  alarming  effects  as  have  been 
referred  to  in  the  foregoing  examples,  but  is  slow  and 
insidious  in  its  action,  unless  in  a  state  of  putrefaction, 

1  Fifth  Annual  Report,  1862. 
2  H 


466  INSPECTION    AND    EXAMINATION    OF    MEAT 

when  it  often  induces  symptoms  of  gastro-intestinal  dis- 
turbance. 

The  Medical  Officer  of  Health  of  Dublin,  where  dis- 
eased meat  has,  until  recently,  been  disposed  of  to  the 
public  in  an  unblushing  manner,  states  that  he  has  re- 
ceived complaints  from  at  least  100  persons  with  respect 
to  the  quality  of  the  meat — nearly  always  beef — which 
they  alleged  had  created  nausea  and  severe  diarrhoea.^ 

He  most  thoroughly  endorses  my  own  views  when  he 
writes,  "  As  a  rule,  bad  water  and  vitiated  air  do  not  kill 
like  arsenic  or  strychnine,  neither  does  the  flesh  of  dis- 
eased animals."  People  are  often  to  be  found  who  habitu- 
ally drink  water  which  is  highly  contaminated  with  sewage; 
whilst  others  are  almost  always  immersed  in  a  vitiated 
atmosphere,  and  exhibit  no  sudden  and  easily  perceived 
injury  thereby.  The  deterioration  of  health  is  gradual  and 
often  subtle.  Now,  although  this  is  undeniably  true,  yet  the 
views  of  the  public  on  this  question  should  have  their  weight; 
for,  without  a  consideration  of  the  subject  in  its  breadth, 
it  is  possible  to  be  led  into  unpractical  conclusions. 
Pecuniary  The  loss  to  this  couutrv  from  the  contagious  diseases 

of  animals  is  over  one  million  a  year,  which  is  felt  by  all 
classes  of  the  community  in  the  increased  prices  of  meat, 
milk,  butter,  etc.  Wliilst  every  effort  is  being  made  by 
the  Legislature,  with  a  due  regard  to  the  injury  inflicted 
on  trade  by  too  many  or  by  too  severe  restrictions,  to 
prevent  the  spread  of  these  diseases,  the  confiscation  of 
animal  food  should  not  be  attempted,  unless  we  possess 
evidence  that  such  meat  is  likely  to  be  in  any  way  pre- 
judicial to  health,  for  meat  is  already  so  expensive  as  to 
be  almost  beyond  the  reach  of  the  agricultural  labourer. 
Then,  on  the  other  hand,  it  cannot  be  right,  as  Dr. 
Cameron   says,  for  the  flesh  of  diseased  animals  to   be 

^   Vide,  Report  on  Pleuro-pneumonic  Flesh  as  Food,  and  Dublin  Journal 
of  Medical  Science,  1871. 


losses. 


INTENDED    FOR    THE    FOOD    OF    MAX  4G7 

palmed  off  on  the  public  as  that  of  healthy  animals,  even 
if  such  meat  is  not  considered  injurious  to  health,  for  the 
flesh  exposed  for  sale  in  the  shops  is  presumably  derived 
from  healthy  animals. 

The  practice  in  the  city  of  London  is  to  condemn  the 
flesh  of  animals  that  have  been  suffering  from  all  febrile 
and  wasting  diseases ;  and  of  any  animal  that  has  been 
killed  immediately  before,  during,  or  after  parturition,  for 
the  reason  that  an  animal  would  not  be  slaughtered  at 
that  time  unless  death  appeared  to  be  imminent. 

Much  meat  finds  its  way  into  the  market  which  is 
simply  inferior  meat,  or  that  of  ill-fed,  half-nourished 
animals ;  or  of  cattle  that  have  died  as  the  result  of 
accident,  such  as  rupture  of  the  stomach  from  eating  too 
much  clover,  etc. 

Sheep  often  die  of  exhaustion  or  mechanical  impedi- 
ments in  parturition.  These  animals  are  much  disposed 
to  over-eat  themselves.  They  distend  themselves  to  such 
an  extent  that  they  at  length  fall  down  in  a  stupefied  con- 
dition or  in  a  fit — they  "  drop,"  as  the  agricultural  people 
express  it.  The  farmer  generally  cuts  the  animal's  throat 
in  haste,  before  it  dies,  and  rapidly  sends  it  to  the  butcher. 
The  meat,  in  such  cases,  must  be  judged  of  by  its  char- 
acters when  dressed  by  the  butcher  for  food.  The  flesh 
of  animals  that  have  died,  and  of  those  that  have  been 
over-driven  or  fatigued,  will  not  keep  long,  and  their  flesh 
is  very  prone  to  rapidly  present  an  unwholesome  appear- 
ance. All  such  inferior  meat  is  sold  at  a  low  price,  with- 
out apparent  injury  to  health,  if  it  does  not  exhibit  the 
characters  of  bad  meat. 

It  is  a  matter  open  to  great  doubt,  as  to  whether  it 
is  justifiable  for  a  Medical  Officer  of  Health- to  attempt  to 
interdict  the  use  of  any  meat  of  inferior  quality  that  does 
not  exhibit  the  characters  of  bad  meat,  respecting  which 
there  exists  on  record  no  evidence  showing  that  the  flesh 


'  Measles." 


468  INSPECTION   AND    EXAMINATION    OF   MEAT 

of  animals  similarly  affected  has  proved  unwliolesome  to 
man. 

3.  Parasitic  Diseases. 

"  Measles  "  of  the  Pig,  Ox,  and  Sheep. — Prof.  Gamgee 
states  that  3  per  cent,  and  probably  5  per  cent,  of 
the  pigs  of  Ireland  are  affected  with  this  disease. 
The  flesh  of  these  animals  is  infested  with  a  parasite 
named  Cysticercus  celhdosus,  which  is  generally  visible  to 


Fig.  75. — Measly  Pork,  by  Dr.  Lewis.    (After  Parkes.) 

the  naked  eye.  They  are  sometimes  so  numerous  that 
when  such  flesh  is  cut  a  crackling  sound  is  emitted.  If 
one  of  these  semi-transparent  little  bladders  is  pricked,  and 
the  contents  are  squeezed  out  on  to  the  slide  of  a  micro- 
scope, the  head  or  sucker  and  ring  of  booklets  are  readily 
seen  with  a  low  power. 

The  measles  of  cattle  is  produced  by  the  Cysticercus 
hovis,  which  becomes  the  Taenia  medio-canellata  of  man. 

Mutton  is  liable  to  the  presence  of  the  Cysticercus  ovis, 
of  which,  in  its  mature  form  as  a  tapeworm,  we  have  but 
little  knowledge. 

When  meat  thus  infested  is  swallowed,  the  outer  coat 


INTENDED    FOR    THE    FOOD    OF    MAN  469 

of  the  vesicle  is  dissolved  by  the  digestive  juices,  liberating 
an  animal  which  is  seen  to  possess  a  bladder-like  tail  and 
a  crown  of  booklets,  with  which  it  attaches  itself  to  the 
coats  of  the  intestines.  Here  it  develops  into  the  Tce^iia 
solium  or  common  tapeworm,  each  joint  of  which  contains 
large  numbers  of  ova  which  are  often  eaten  by  animals. 

The  origin  of  the  echinococcus  or  hydatid  disease  is 
thus  described  by  Drs.  Woodman  and  Tidy  {Forensic 
Medicine) : — "  A  piece  of  diseased  offal  is  eaten  by  a  dog 
which  passes  by  the  bowels,  either  in  the  field  or  in  the 
stream,  segments  of  the  developed  worm  {Tmnia  echino- 
coccus). Cattle  and  sheep  swallow  these  segments.  At 
last  the  animal  that  has  swallowed  them  becomes  the  food 
of  man,  and  then  the  larval  tapeworm  becomes  a  bladder- 
like hydatid.  In  the  ox  it  goes  to  the  peritoneal  cavity ; 
in  the  sheep  to  the  brain,  producing  '  staggers  ' ;  and  in  the 
man  to  the  liver." 

The  "sturdy,"  "turnsick,"  or  "gid"  of  sheep  is  in- 
duced by  the  presence  of  a  hydatid  in  the  brain,  named 
Ccenurus  cerebralis,  the  mature  form  of  which  is  named 
Tcenia  ccenuris.  The  Strongylus  filar ia  is  a  parasite  that 
is  found  in  the  lungs  of  the  calf  and  lamb,  where  it  pro- 
duces what  has  been  termed  phthisis  pulmonalis,  vermin- 
alis,  or  parasitic  bronchitis. 

In  diagnosing  the  presence  of  cysticerci  in  meat,  it  is 
necessary  to  recognize  the  booklets. 

The  treatises  of  Cobbold,  Leuckart,  and  Klichenmeister, 
may  be  advantageously  consulted  by  those  interested  in 
the  study  of  the  transformations  of  these  parasites. 

Tlie  trichina  spiralis  (dpi^,  a  hair)  is  observed  most  Trichina 
frequently  in  the  flesh  of  the  pig.     It  has  been  declared^  ^^'^'^'^' 
to  have  been  found  in  mutton  and  frequently  in  beef,  and 
that  the  reason  that  this  parasite  has  always  been  asso- 
ciated with  pork  is,  that  in  the  flesh  of  the  pig  its  cysts 

1  Piiblic  Health,  February  23,  1877,  p.  131. 


470  INSPECTION    AND    EXAMINATION    OF   MEAT 

are  most  easily  seen.  It  has  been  noticed  in  rabbits,  horses, 
and  many  other  animals.  Wliereas  hogs  have  been  sup- 
posed to  get  their  trichinae  from  eating  rats  which  have  been 
found  largely  infested  with  them,  it  has  been  conjectured  by 
some  that  rats  and  mice  derive  them  from  trichinosed  pork. 
They  are  so  numerous  that  a  piece  of  muscle  the  size  of  a 
pin's  head  has  been  estimated  by  Vogel  to  contain  12,000 
trichinae.  They  are  most  abundant  at  the  extremities  of 
muscles  at  their  insertion  into  bones  and  tendons. 

The  symptoms  of  trichinosis,  being  enumerated  in 
many  books  which  are  easily  accessible  to  medical  men, 
require  no  description.  The  best  accounts  of  it  are  from 
the  pens  of  German  physicians.  A  good  summary  of 
their  views  is  to  be  found  in  the  Eeport  on  Trichinae  and 
Trichinosis,  by  Dr.  W.  C.  W.  Glazier  (U.S.  Marine  Hospital 
Service).  The  symptoms  may  be  arranged  during  the 
jDrogress  of  the  disease  in  three  stages,  as  has  been  pointed 
out  by  Dr.  Eichardson : — (1)  A  stage  of  intestinal  irrita- 
tion, corresponding  with  the  full  development  of  the 
trichinae,  which  has  sometimes  been  mistaken  for  cholera ; 
(2)  a  stage  of  moderate  fever  attended  with  pains  in  the 
muscles,  like  those  of  rheumatism,  corresponding  with  the 
time  when  the  embryos  find  their  entrance  into  the 
muscles  and  are  becoming  encysted ;  (3)  a  prolonged  and 
chronic  stage  of  impaired  muscular  movement  with  emacia- 
tion, corresponding  with  the  period  when  the  larvae  are 
entirely  encysted  in  the  muscle  and  are  fixed  in  position. 
If  the  case  proceeds  to  a  fatal  termination,  death  either 
results  from  coma  or  from  severe  pneumonia.  It  is  often 
very  difficult  to  diagnose  the  second  stage  from  that  wliich 
presents  itself  to  the  medical  man  when  summoned  to  a 
case  of  enteric  fever. -^     The  indications  of  the  thermometer 

^  If  the  outbreak  on  board  the  Reformatory  School  ship  Cornwall 
in  1879  was  in  truth  trichinosis,  it  ■would  seem  that  the  existence  of  rose- 
coloured  spots  and  hemorrhage  from  the  bowels  are  symptoms  not  diag- 
nostic of  enteric  fever. 


INTENDED    FOR   THE    FOOD    OF    MAN 


471 


may  render  some  help  when  coupled  with  the  cedema, 
especially  of  the  face,  and  profuse  perspirations  usually 
characteristic  of  trichinosis.  Trichinae  have  been  found  in 
all  countries,  if  search  has  been  made  for  them.    American 


Trichinosis 
and  Enteric 
Fever. 


Fig.  76. — Fever  curve  of  a  mild  case  of  trichinosis  (Maurer,  Ziemssen,  iii.,  632). 


atvofdi5l     E 
-^  •'  e   m.e    in.e .  m.e    m.e    Tw.e    m.e    m.e    m.e    m.e    m.e 


Fig.  77. — Range  of  Temperature  during  the  first  12  days  in  a  case  of  Enteric  Fever. 
TO.  e.  morning  and  evening  CWiinderlich). 

pork  has  earned  a  suspicious  character  by  reason  of  the 
occurrence  of  outbreaks  of  trichinosis  in  the  United  States, 
and  the  discovery  of  trichinae  in  imported  hams.  This 
disease  is  rarely  seen  in  this  country,-^      Epidemics  have 

^  Two  or  three  outbreaks  have  been  reported : — one  at  Thaxted,  in 
•whicli  more  than  forty  persons  suffered  from  the  consumption  of  sausages 
made  from  salt  pork,  probably  foreign,  which  contained  specimens  of  the 
trichinae  spiralis  ;  and  another  in  a  family  in  Cumberland,  ft-om  eating 
trichinae  infected  pork. — Brit.  Med.  Journal,  April  29,  1871. 


472 


INSPECTION    AND    EXAMINATION    OF    MEAT 


Outbreaks,  been  reported  from  Eussia,  Sweden,  Denmark,  Switzerland, 
and  even  India,  but  the  headquarters  of  the  disease  is 
situated  amongst  our  neighbours,  the  Germans,  who  have 
such  an  unconquerable  predilection  for  uncooked  or  im- 
perfectly cooked  sausages.  The  first  recorded  was  observed 
in  Dresden  and  in  Plauen-^  in  1860.  Soon  afterwards  out- 
breaks occurred  at  Stolberg,  Eiigen,  Hettstadt,^  Custen  and 
Wurmsdorf,  Hedersleben,  Calbe,  Burg  near  Madgeburg,  in 


Fig.  78. — Encapsulated  Trichina  Spiralis  x  250. 


Anhalt,  Leipsic,  Jena,  Eisleben,  Quedlinburg,  Dessau,  Stass- 
furt,  and  Weimar.  At  Hettstadt  103  persons  were  affected, 
and  83  died.^  The  chief  trichinae  district  has  been  in 
the  past  in  the  vicinity  of  Madgeburg.  In  Dr.  Glazier's 
report  references  are  made  to  no  less  than  150  epidemics 
of  trichinosis  (from  1860  to  1877  inclusiA^e),  3800  cases 
with  281  deaths  being  arranged  in  a  list,  and  700  cases 
with  50  deaths  not  being  therein  included.  There  is  a 
great   difference   in   the   susceptibility  of  individuals   to 

^  Annates  d'HygUne,  October  1863. 

2  Brit.  Med.  Journal,  January  16,  1864. 

^  Vide  Report  by  Dr.  Thudichum  on  the  "Parasitic  Diseases  of  Quad- 
rupeds used  for  Food,"  in  Seventh  Report  of  Medical  Officer  of  Privy 
Council,  1864. 


INTENDED    FOR    THE    FOOD    OF    MAN 


473 


trichinosis  infection,  some  being  quite  unaffected  by  the 
consumption  of  trichinosed  flesh. 

Modes  of  Detection. — Sausage  manufacturers  in   Ger- Modes  of 
many  are  said  to  have  the  eyes  of  all  pigs  after  slaughter 
examined    microscopically    by    a    medical    man,    as    the 


Fig.  79. — From  human  body  dj  mg  during  the  Hedersleben  epidemic.    Trichinae  about 
7  weeks  old,  completely  developed,  but  without  a  trace  of  capsule.    (Leuckart.) 

muscles  of  the  eye  are  the  first  affected.  A  portion  of  the 
flesh  removed  from  underneath  the  tongue  is  often  exam- 
ined ;  but  the  diaphragm,  psoas,  biceps,  and  masseter 
muscles  have  been  found  to  contain  trichinse  in  greater 
abundance  than  the  other  muscles  of  the  body.  Meat 
suspected  to  contain  trichinse  may  be  examined  thus : — 
A  thin  section  having  been  made  with  a  Valentine's 
knife,  or  by  the  aid  of  one  of  the  several  microtomes  now 
obtainable,  is  immersed  for  a  few  minutes  in  a  mixture 
of  liq.  potassee  1  part  and  water  8  parts,  until  the  muscle 
becomes  clear.  If  they  are  present  white  specks  appear, 
in  which  the  worm  is  seen,  by  the  aid  of  the  microscope, 
coiled  up.  A  drop  or  two  of  weak  hydrocliloric  acid  will 
often  render  the  parasite  more  visible.  A  little  ether 
may  be  added  with  the  same  object  in  fat  meat.  Wlien 
the  capsules  are  calcified,  they  can  be  plainly  seen  with 
the  naked  eye. 


474 


DfSPECTIOX    AXD    EXA3IIXATI0N    OF    MEAT 


A  ready  way  of  detecting  these  animals  in  flesh,  is 
that  of  soaking  it  in  a  strong  solution  of  logwood,  which 
dyes  the  meat  but  does  not  colour  the  trichinge. 

Care  must  be  taken  to  avoid  confounding  these  para- 
sites with  Eainey's  corpuscles  or  capsules  (Psorospermia) 
which  have  on  their  surface  minute  hair-like  markings.-^ 
These  bodies  were  observed  in  the  flesh  of  cattle  that  died 


Rainey's 
corpuscles 
(Psorosper- 
mia). 


Fig.  80. — A  Psorosperm  lying  loose  among  muscular  fibres. 

of  rinderpest,  when  the  disease  entered  the  country  and 
destroyed  our  herds  in  1865,  by  some  who  were  not 
accustomed  to  esamine  meat  microscopically,  and  who 
discovered  in  their  presence,  so  they  thought,  the  cause 
of  the  disease.  The  muscle  trichina  spiralis  is  easily 
distinguished  from  the  Filaria  sangui/iis  hominis  (found 
in  the  blood  and  urine  of  cases  of  chyluria)  and  from 

^  Phil.  Transactio'iis,  1S57. 


INTENDED    FOR    THE    FOOD    OF    MAN  475 

the  embryo  of  the  Draxumculus  (Guinea-worm),  by  ha\-ing 
a  sharp  head  and  a  blunt  tail,  whereas  the  heads  of  the 
latter  are  round  and  the  tails  are  sharp. 

An  instrument,  termed  a  harpoon,  was  debased  and 
employed  some  years  ago  in  Germany,  when  such  large 
numbers  of  people  suffered  from  the  disease,  for  diagnosing 
the  presence  of  the  parasites  in  the  human  muscles,  and 
for  noting  their  increase  or  diminution.  It  resembled  a 
trocar  with  a  minute  forceps  at  the  pointed  extremity, 
which  was  plunged  into  the  living  muscle.  The  small 
pincers  ha^dng  been  opened  by  the  aid  of  some  mechanism 
in  the  handle,  a  bit  of  the  muscular  tissue  was  seized  and 
withdrawn.  This  minute  portion  of  muscle  was  examined 
microscopically,  and,  if  present,  the  number  of  trichinae  in 
the  quantity  were  counted. 

Tiie  Fluke  (Distoma  hepatlcum  =  ?;^e  rot)  is  a  para- The  Fiuke. 
site  -^  that  is  found  in  the  livers  of  men  and  animals, 
especially  the  sheep.  The  carcase  has  a  flabby,  emaciated 
appearance,  and  the  meat  is  of  a  greenish-yellow  colour 
from  bile  staining.  Mr.  Yacher's  memoranda  respecting 
tliis  disease  are  as  follows : — "  Due  to  presence  in  bile 
ducts  of  little  animals  provided  with  suckers,  in  shape 
like  soles,  and  measuring  from  1  to  1-g-  inch  long,  and 
about  -|  inch  wide.  Sometimes  so  numerous  as  to  block 
up  bile  ducts.  SjTuptoms,  jaundice  and  dropsy."  Many 
regard  sheep's  liver,  thus  infested,  as  a  dainty  dish.  The 
eatiQg  of  garden  snails,  whelks,  mussels,  shell  fish,  etc.,  is 
considered  as  another  mode  by  which  men  become  affected 
with  this  disease,  which  occasions  heematuria  and  dysen- 
tery. The  rot  is  the  name  given  to  this  disease  as  it 
occurs  amongst  sheep,  thousands  of  which  it  kills  annually. 

Old  farmers  consider  that  the  parasite  flourishes  on 
unsound   marshy   land   especially   in   autumn,  and    that 

^  A  good  description  of  the  transfonnations  undergone  by  this  parasite 
is  to  be  found  in  Aitken's  Practice  of  Medicine. 


476  INSPECTION    AND    EXAMINATION    OE    MEAT 

they  are  able  to  indicate  the  parts  of  large  fields  which 
give  "  liver  rot "  to  their  sheep. 
Conclusions.  Conclusious. — Salting  does  not  kill  cysticerci,  although 
a  high  temperature  and  smoking  are  said  to  do  so.  In 
India  such  meat  is  allowed  to  be  eaten  if  well  cooked. 
Cooking,  salting,  and  smoking  simply  lessen  the  danger, 
even  if  efficiently  performed,  and  do  not  remove  it. 

Much  meat  that  is  eaten  is  very  unwisely  consumed 
in  a  raw  state,  and  more  frequently  in  a  half- cooked 
condition. 

Salting,  like  cooking,  is  generally  performed  in  an 
irregular  ever -changing  manner,  the  brine  sometimes 
being  used  so  many  times  as  to  have  become  actively 
poisonous. 

All  meat  which  contains  cysticerci,  trichinae,  flukes, 
and  all  other  animal  parasites  which  are  apt  to  infest 
man,  should  be  condemned  as  unfit  for  human  food. 

In  the  reign  of  Henry  III.  butchers  who  sold  measly 
pork  were  placed  in  the  pillory. 

Immature  Veal  and  Lamh. 

Immature  In  somc  placcs  there  is  a  chronic  state  of  irritability 

L^b'^*^^  maintained  between  the  Health  Authority  and  the  butchers, 
as  to  whether  "  sHnk  "  meat  is  fit  for  food,  and  my  opinion 
has  been  sought  to  settle  the  vexed  question.  In  Halifax 
a  bye-law  has  been  passed  condemning  calves  under  21 
days  old,  or  under  48  lbs.  in  weight.  In  dairy  counties, 
where  farmers  are  desirous  of  getting  rid  of  calves  as 
quickly  as  possible,  they  are  killed  when  only  14  days 
old.  Cows  very  readily  slip  their  calves,  and  the  flesh 
of  such  animals  is  always  inferior,  being  innutritions  and 
indigestible.  These  immature  calves  and  lambs  are  some- 
times healthy,  and  at  others  weakly  and  even  unliealthy. 
The   last-named   furnish   meat  which   is  pale  and  soft. 


INTENDED    FOR    THE    FOOD    OF    MAN  477 

The  flesli  of  these  prematurely -cast  calves  and  lambs 
cannot  be  deemed  unwholesome  unless  diseased  or  born 
of  diseased  cows  or  ewes,  but  constitutes  meat  of  inferior 
quality,  and  as  such  should  be  sold.  The  Germans  con- 
sider that  healthy  calves  less  than  8  to  10  days  old 
furnish  meat  of  diminished  value. 


Poisonous  Pork,  Ham,  Sausages,  etc. 

Frequently  cases  occur  in  which  pork,  in  some  form  Poisonous 
or  other,  has  acted  on  those  who  have  eaten  it  as  an  ^nd  ' 
irritant  poison.      The  remarkable  outbreaks  of  choleraic  sausages. 
diarrhoea  at  Welbeck  in   1880,  and   at   ISTottingham  in 
1881,  must  be  fresh  in  the  recollection  of  medical  officers 
of  health.       In  the  former  more  than   72  persons,  and 
in  the  latter    15   persons  sufi'ered.      There  was  an  incu- 
bation period  varying  from  12  to  48  hours.      The  symp- 
toms were  the  same  in  all — shivering,  headache,  thirst, 
giddiness,  faintness,  vomiting,  cold  sweats,  diarrhoea,  great 
prostration,    etc.       Violent    enteritis    and  '^s?'- 

pneumonia   were    produced    in    both    out-  ^  1^ 

breaks.       The  same  kind  of  bacillus  was  <3^ 

found  in  the  blood  of  the  fatal  cases  in  ^ 

each  outbreak.      They  are  rounded  at  their  ^  ,  ^  ^'!^'  . "  „ 

■^     _     _  Isolated  bacilli  from 

extremities,  some  containing  spores.  artery  of  kidney, 

-r-,  •  j_       ^         Ay       ^•  -\     •  ij.        some  of  wliieh  con- 

Expermients  by  feeding  and  moculat-    ^am  spores  x  too 
ing  animals  with  the  pork  and  with  the    '^iam.  (Riein.) 
cultivated   bacilli   produced  fatal   results   by  pneumonia 
and  peritonitis. 

The  conclusion  arrived  at  was,  that  either  the  bacillus 
itself,  or  some  virus  or  ptomaine  essentially  associated 
with  it,  was  the  active  agent  in  the  production  of  these 
alarming  epidemics. 


CHAPTEE    XLI 

INSPECTION    AND    EXAMINATION    OF    POULTRY,    GAME,    ETC. 

As  violent  gastro-intestinal  disturbances  are  often  excited 
by  the  consumption  of  game  in  a  very  "  high  "  condition, 
a  Medical  Officer  of  Health  would  be  warranted  in  pro- 
nouncing any  birds  or  hares  exhibiting  a  state  of  putridity 
as  injurious  to  health.  Pheasants  fed  on  the  laurel  have 
created  illness  when  eaten.  Poultry  is  not  improved  by 
"  hanging,"  like  game,  and  when  it  begins  to  emit  a  dis- 
agreeable odour  is  so  stale,  as  to  be  approaching  a  state 
in  which  it  should  be  condemned. 

Birds,  like  mammals,  are  subject  to  a  sort  of  variola 
which  is  contagious.  Powls,  turkeys,  and  geese  are 
sometimes  affected  by  it.  The  presence  of  pustules  on 
the  body  of  the  bird  renders  it  for  the  time  unsaleable. 

Cholera  and  anthrax  in  poultry  are  diseases  that  are 
not  known  to  render  it  injurious  to  the  health  of  man 
when  eaten,  although  there  is  a  strong  suspicion  that 
obscure  forms  of  illness  may  have  been  induced  by  the 
consumption  of  poultry  thus  affected.  Turkeys,  geese, 
ducks,  and  pigeons  are  all  subject  to  cholera.  Mr.  Vacher 
writes  respecting  it :  "  Plesh  redder  than  natural.  Heart 
speckled  with  red  or  dark  spots,  often  inside  and  out. 
Intestine  inflamed,  with  red  spots  or  livid  patches." 

Pheasants,  pigeons,  turkeys,  and  fowls  are  known  to 
be    attacked    with    so-called    diphtheria.       The   Wiener 


INSPECTION    AND    EXAMINATION    OF   POULTRY,  ETC.     479 

Allgemeine  Mcdicinische  Zeitung  informs  us  that  Prof. 
Gerhart  of  Wiirzburg  has  carried  out  a  number  of  ex- 
periments which  have  led  him  to  the  conclusion  that  this 
disease  may  be  communicated  to  man  by  these  birds. 
An  outbreak  of  diphtheria  occurred  in  1882-83  amongst 
the  poultry  at  Nesselhausen,  in  Baden.  Two-thirds  of  all 
the  labouring  persons  employed  about  the  fowl -raising 
establishment  there  became  ill  with  ordinary  diphtheria, 
and  one  man  conveyed  the  infection  to  his  three  children. 
No  other  cases  of  diphtheria  occurred  during  all  this 
time  in  the  town  itself  or  in  its  neighbourhood.  A  similar 
outbreak  has  been  observed  amongst  the  inhabitants  and 
poultry  of  Marseilles,  which  has  been  described  by  Dr. 
Nicati  in  the  Eevue  d'HygUne  et  de  Police  Sanitaire,  No.  3, 
March  1879.  MM.  Delthill  and  Bouchard  at  the  recent 
Nancy  Congress  expressed  their  belief  from  observation 
in  the  existence  of  a  connection  between  diphtheria  in 
children  and  a  disease  amongst  fowls  and  pigeons  known 
as  the  "  pip  "  or  "  croup." 

It  is  often  necessary  to  have  rabbits  confiscated,  as 
they  are  frequently  offered  for  sale  in  a  putrid  state. 


CHAPTEE    XLII 

INSPECTION   AND    EXAMINATION    OF    FISH 

Although  the  quantity  that  is  annually  condemned 
throughout  this  country  is  very  great,  an  immense  amount 
of  unwholesome  fish  is  consumed  by  the  poor,  and  creates 
diarrhoea,  nettle  rash,  and  other  affections.  Mackerel 
cannot  be  eaten  in  too  fresh  a  state ;  whilst  whiting  is 
improved  by  hanging  for  a  short  time,  when  the  weather 
is  not  hot,  if  dusted  with  salt. 

Wlien  fish  has  changed  colour,  and  has  an  offensive 
or  ammoniacal  odour,  it  should  be  seized  as  unfit  for 
human  food. 

A  bright  red  colour  of  the  gills  cannot  be  relied  on  as 
a  sign  of  freshness,  for  they  are  often  tinted  by  the  sales- 
man. The  diminution  in  the  brilliancy  of  the  colours  of 
a  fish,  and  the  extent  of  drooping  of  its  tail  when  it  is 
held  in  the  hand,  are  the  best  signs  of  staleness. 

Some  fish  in  the  tropics  are  always  poisonous,  whilst 
others  are  poisonous  to  some,  but  not  to  all  persons,  and 
others  are  at  times  only  injurious.  Pilchards,  mussels,^ 
eels,^  crabs,^  lobsters,  oysters,  mackerel,^  turtle,  and  sar- 
dines,^ have  at  times  produced  very  unpleasant,  or  dan- 

1  3£edical  Times  and  Gazette,  November  1,  1862,  April  30,  1864,  and 
Guy's  Hospital  Reports,  October  1850,  and  Lancet,  March  7,  1846,  and 
May  5,  1866. 

2  Lancet,  June  21,  1873.  s  Za7icet,  October  27,  1866. 

*  Lancet,  July  30,  1864.  ^Medical  Times  and  Gazette,  December  13,  1862. 


INSPECTION    AND    EXAMINATION    OF   FISH  481 

geroiis,  and  even  fatal  results.  Most  commonly  dyspepsia,  symptoms 
swelling  of  the  tongue  and  fauces,  itching  of  the  eyes  poisonous. 
and  eyelids,  an  eruption  resembling  nettle  rash,  with 
great  irritation,  are  the  symptoms  complained  of  Less 
frequently  numbness  of  limbs,  feeble  action  of  heart  and 
coma,  and,  in  rare  cases,  death  has  resulted.  The  nature 
of  the  animal  poison  contained  in  these  fish  is  unknown. 
It  is,  in  some  cases,  thought  to  be  due  to  some  particular 
food  in  which  the  fish  has  indulged,  and  in  others  to  be 
developed  only  during  the  breeding  time.  There  is  some 
suspicion  that  shrimps,  cockles,  and  oysters,  when  affected 
with  some  parasitic  fungus,  may  acquire  properties  poison- 
ous to  man,  and  create  choleraic  symptoms  amongst  those 
who  eat  them.^  Stale,  decomposing  fish  are  often  plunged 
into  brine,  which  is  supposed  to  stop  the  putrefactive 
process.  Such  salted  fish  has  often  produced  illness. 
An  outbreak  occurred  in  1878  in  St.  Petersburg,  attack- 
ing more  than  100  persons,  which  resulted  from  the 
consumption  of  salt  codfish.  This  fish  was  found,  on 
subsequent  examination,  to  present  a  yellow  hue,  the 
flesh  being  friable  and  a  little  mouldy.  The  muscular 
fibres  were  shown  by  the  microscope  to  be  in  a  state  of 
decay.  The  poisonous  symptoms  produced  by  some  salted 
and  smoked  fish  have  been  ascribed  to  a  ptomaine  secreted 
by  a  microbe. 

Mr.  Yacher  considers  that  salmon  affected  severely 
with  the  fungus  disease  known  as  "  the  salmon  disease  " 
should  be  seized  if  exposed  for  sale. 

^  Report  on  East  Kent  for  1884,  by  Dr.  Eobinson. 


2  I 


CHAPTEE    XLIII 

MEAT    OF    POISONED    ANIMALS 
Intentional  Animals    are  often   injured   or  destroyed   by  animal   or 

oraccideutal  iii  •  m  j.j^-i  ^  ii 

poisoning.  Vegetable  poisons.  Ine  meat  oi  animals  may  be  rendered 
unwholesome  or  poisonous  by  tlie  food  eaten,  or  by  poisons 
administered  intentionally  or  taken  accidentally.  Cattle 
and  horses,  poultry  and  game  are  sometimes  destroyed 
by  arsenic.  Dr.  Ashby  records  the  case  of  the  poisoning 
of  beasts  by  water  accidentally  impregnated  by  arsenious 
acid,  which  had  entered  the  earth  at  a  spot  fifty  yards 
away  from  the  well. 

Cattle  and  horses  are  injured  or  destroyed  by  eating 
yew  leaves,  bryony,  meadow  saffron,  etc.  The  stomachs 
and  alimentary  canals  of  animals  thus  destroyed  will  be 
found  the  seat  of  more  or  less  inflammation.  Fragments 
of  the  vegetable  substance  may  also  be  discovered. 
Farmers  often  seek  the  advice  of  the  health  officer  on 
these  cases,  according  to  my  experience. 

The  flesh  of  game  is  apt  to  be  rendered  unwholesome 
by  the  food  eaten.  The  flesh  of  hares  fed  on  the  rhodo- 
dendron, chrysanthemum,  and  after  coursing^  (when  they 
have  a  resinous  taste  and  odour,  and  have  been  considered 
to  be  in  a  state  of  ursemia),  has  been  found  to  exert 
poisonous  effects. 

1  Lancet,  Sexrtember  27,  1862,  and  British  Medical  Journnl,  November 
30,  1878,  p.  817. 


MEAT    OF    POISONED    ANIMALS  483 

Pheasants  fed  on  the  laurel  have  created  illness  when 
eaten.  A  case  is  recorded  where  the  flesh  of  a  turkey 
proved  poisonous/  and  no  poison  could  be  found  on 
analysis. 

Fish  are  sometimes  destroyed  by  cocculus  indicus,  but 
more  frequently  by  lime,  both  being  thrown  into  ponds 
and  streams  where  they  abound. 

1  Medical  Times  and  Gazette,  March  18,  1871. 


CHAPTEE    XLIV 

DESTEUCTION    OF    COXDEMXED    FLESH 

The  question  often  arises  as  to  how  flesh,  which  is  con- 
sidered to  be  unfit  for  human  food,  should  be  disposed  of. 

If  it  is  handed  over  to  the  knacker  to  be  sold  as  food 
for  cats,  there  is  a  risk  lest  the  meat  should  ultimately 
find  its  way  to  the  butchers'  stalls  of  the  low  parts  of  our 
cities  and  towns,  and  be  sold  to  the  poor.  If  the  meat 
is  not  unsuitable  for  dogs,  it  may,  with  greater  safety, 
although  with  some  risk  in  the  case  of  some  diseases, 
be  sold  as  food  for  packs  of  hounds. 

If  meat  is  buried,  there  is  a  danger  lest  it  may  partly 
be  brought  to  light  by  dogs. 

If  it  is  buried  too  deep  to  allow  of  such  interference, 
the  meat  is  still  liable  to  get  into  the  market  by  the  aid 
of  a  resurrectionist. 
Resurrec-  Cascs  of  the  resurrcctiou  of  diseased  pio-s  are  recorded 

tion  of  .  ►-  H 

diseased  HI  the  Sanitary  Record  of  February  16,  18//,  page  105, 
meat.  ^^^  February  5,  1876,  page  96.  Ptemembering  that 
every  part  of  an  animal,  even  to  its  bones  and  hoofs, 
whether  diseased  or  not,  possesses  a  distinct  money  value, 
the  disinterment  durino;  dark  niohts  of  such  bodies  is  not 
to  be  wondered  at. 

Perhaps  the  best  mode  of  preventing  the  sale  of 
condemned  meat  as  human  food  is  to  unpregnate  it  with 
some  substance  that  will  render  it  unsaleable. 

In  the  city  of  London,  where  vast  quantities,  as  much 


^  cwt. 
1  cwt. 


DESTRUCTION    OF    CONDEMNED    FLESH  485 

sometimes  as  35  tons  (=100  oxen),  of  putrid  and 
diseased  meat,  dressed  for  sale,  are  seized  in  one  day,  the 
meat  is  plunged  into  a  bath  of  the  following  composition, 
preparatory  to  its  conveyance  in  carts  to  Deptford,  where, 
by  the  help  of  machinery,  it  is  separated  into  meat,  fibre, 
fat,  and  bone,  and  subsequently  utilized  in  trade : — 

D7\  Sedgwick  Saunders'  Chemical  Bath. 

Chloride  of  calcium         ....  2  cwts. 

Chloride  of  sodium 

Sulphate  of  iron  (green  copperas) 

Carbazotic  or  picric  acid  ...  2  lbs. 

Water 300  gals. 

The  chlorides  deodorize  putrid  and  stinking  meat, 
whilst  the  picric  acid  and  sulphate  of  iron  discolour  it,  and 
render  it  so  disgusting  to  the  taste,  as  to  remove  all  fear 
of  its  appropriation  for  human  food.^  If  the  meat  is 
covered  with  the  fluid,  it  can  thus  be  kept  free  from  smell 
for  several  weeks. 

In  country  districts,  where  seizures  of  meat  are  few 
and  far  between,  condemned  meat  may  be  most  con- 
veniently rendered  unsaleable  by  making  deep  incisions 
into  the  flesh,  and  pouring  therein  imintre  carbolic  acid, 
which  possesses  a  disgusting  odour.  Creosote  and  oil 
of  turpentine  have  also  been  used. 

Instruments  have  been  invented  for  introducing  such 
fluids  readily  into  various  parts  of  a  carcase.  Defays 
made  a  tube  with  a  lancet  point,  provided  with  a  flask 
containing  the  fluid ;  and  Kopp  recommended  a  spatula 
with  sharp  edges,  grooved  on  the  surface,  which  is  dipped 
into  the  fluid  each  time  that  it  is  plunged  into  the  flesh. 

^      Eeport  upon  various  Methods  of  dealing  with  Meat  seized  as  i;nfit 
for  human  food  in  the  City  of  London,"  by  Dr.  Sedg^vick  Saunders. 


CHAPTEE    XLV 

INSPECTION   AND   EXAMINATION    OF    FRUIT    AND    VEGETABLES 

Vegetables,  like  animals,  seem  to  possess  wonderful 
powers  of  discrimination  between  tlie  poisonous  and  non- 
poisonous  in  their  food.  It  is  wise  to  avoid  water-cress 
wliich  has  been  grown  in  effluent  water  below  the  standard 
of  purity,  and  also  strawberries,  earlj  cauliflowers,  etc., 
which  have  been  recently  "top-dressed"  with  manure, 
if  we  have  an  opportunity  of  choice.  Asparagus — a 
vegetable  that  rapidly  confers  when  eaten  a  character- 
istic odour  on  the  urine — has  been  found,  when  raised 
in  certain  localities,  to  produce  colic  and  diarrhoea- 
symptoms  which  have  been  attributed  to  the  presence 
of  minute  amounts  of  sulphide  of  carbon  in  the  soil. 

Half-decomposed  fruit  and  vegetables  are  deleterious 
to  health,  exciting  diarrhoea.  Unripe  fruit,  especially 
plums,  are  exceedingly  hurtful  to  young  children.  In 
times  of  cholera  or  epidemic  diarrhoea,  the  exposure  of 
such  for  sale  would  justify  seizure. 

Every  now  and  then  the  opinion  of  the  Medical 
Officer  of  Health  is  sought  by  the  Nuisance  Inspectors,  as 
to  whether  quantities  of  fruit  and  vegetables  are  or  are 
not  injurious  to  health.  Simply  damaged  and  stale  fruit 
and  vegetables  cannot,  of  course,  be  so  regarded ;  but  all 
decomposing  and  offensive  vegetable  matter  should  be 
condemned. 


INSPECTION    AND    EXAMINATION    OF    FRUIT,   ETC.       487 

The  poor  are  the  chief  consumers  of  this  unwholesome 
food.  With  vast  numbers  fresh  fruit  and  vegetables  are 
impossible  luxuries.  I  cannot  but  think  that  an  immense 
profit  is  to  be  made  by  any  enterprising  company  that 
would  undertake  to  supply  the  wants  of  the  poor  of  a 
great  city  with  fresh  vegetables,  at  prices  within  their 
reach ;  for  the  present  arrangement,  whereby  the  poor  are 
supplied  with  stale  vegetables,  is  attended  with  such  an 
enormous  waste  of  these  important  necessaries  of  healthy 
human  life. 


CHAPTEE   XLVI 

TINNED    PEOVISIONS 

Peesek^t:d  Australian  meats,  and  American  tinned  fish, 
fruits,  and  vegetables,  etc.,  are  apt  to  become  impregnated 
with  small  quantities  of  lead  from  the  solder  and  tin 
which  frequently  contains  as  impurities  arsenic  and 
antimony.  The  vegetable  and  other  acids  associated  with 
these  provisions  have  a  corrosive  effect,  which  is  increased 
by  the  galvanic  action  set  up  between  the  metals.  Copper, 
which  is  used  to  impart  a  brilliant  green  colour  to  peas 
and  French  beans,  is  often  to  be  detected.  It  is  reported 
that  the  importation  of  these  foods  from  abroad  has  led 
to  the  production  of  inferior  imitations  manufactured  out 
of  damaged  food  in  the  East  End  of  London.  A  great 
deal  of  imperfectly-preserved  food  of  this  kind  has  been 
employed  in  the  neighbourhood  of  the  metropolis  for  the 
feeding  of  pigs,  where  collections  of  this  decomposing 
material  have  proved  a  nuisance. 


CHAPTEE    XLVII 

INSPECTION   AND    EXAMINATION    OF    CORN 

Corn  is  generally  understood  to  comprehend  the  grains  of 
wheat,  barley,  and  oats,  to  the  exclusion  of  those  of  rye, 
maize,  etc. 

The  differences  between  the  appearance  of  different 
kinds  and  samples  of  wheat  and  barley,  as  indications  of 
varying  degrees  of  quality,  can  be  better  learnt  from  any 
farmer  than  from  a  description ;  whilst  almost  every 
medical  man  necessarily  acquires  practical  experience  in 
diagnosing  good  oats. 

Grains  of  corn  are  sometimes  damaged  and  rendered 
of  little  value  by  a  "  growing  out."  When  such  corn  is 
ground  the  flour  is  known  in  trade  as  "  weak."  Such 
flour  cannot  strictly  be  said  to  be  injurious  to  health, 
except  as  taking  the  place  of  an  equal  quantity  of  more 
nutritious  material. 

Grains  of  corn  should  be  free  from  smell,  sprouting, 
discoloration,  and  any  evidence  of  insects  or  fungi. 

The  insects  sometimes  found  in  corn,  and  in  meal  of 
different  kinds,  are  the  weevil  and  the  Acarus  farince,  the 
former  visible  to  the  naked  eye,  and  the  latter  ^     The  weevil. 

by  the  aid  of  a  pocket  lens  or  microscope.     If    ^^  n^ 
grains  are  seen  to  be  pierced  with  minute  holes,       fio.  82. 
and  are  found  to  have  been  deprived  of  their  arfa'or  welvu.' 
contents,  the  weevil  is  the  culprit. 


490 


INSPECTION    AND    EXAMINATION    OF    COEN 


"  Ear- 
cockle.' 


The  wheat 

niidse. 


Ergot. 


Earcockle,"  "  Purples,"  or  "  Peppercorn/'   are  names 

applied  to  a  blighted 

condition  of  ears  of 

corn,  in   wliich    the 

grains  become  green 

and  afterwards  black. 

The  grains  are  filled 

with   a    cotton  -  like 

Fig.  83.-vibrio  tritici,  X  100  diam.  substancc  in  placc  of 

flour,  which,  when  moistened,  is  seen  to  be  composed  of 

animalcules  in  a  state  of  great  activity  (  Vibrio  tritici). 

The  wheat  midge  {Cecidomyia  tritici)  is  a  great  enemy 
of  the  farmer,  who  sometimes  sees,  early  in  June,  myriads 
of  these  little  flies  hovering  about  the  wheat 
for  the  purpose  of  depositing  its  eggs  within 
the  blossoms.  The  caterpillars  that  are  pro- 
duced from  these  eggs  interfere  with  the  de- 
velopment of  the  ovary,  so  that  abortive  grains 
are  alone  found.  Small  birds  happily  prey  on 
the  midge,  and  thus  lessen  the  mischief. 

Certain  vegetable  parasites  also  deteriorate 
corn  in  value,  and  sometimes  render  it 
poisonous. 

Ergot  (Oidium  ahortifaciens)  is  a  fungus 
K^  which  shows  a  decided  preference  for  rye,  but 
also  attacks  the  ears  of  wheat. 

In  countries  where  rye  bread  is  eaten  to 
a    large    extent,   a    peculiar    disease,   named 
Fig.  84.        ergotism,  has  prevailed  epidemically.   This  dis- 

Oidium       aborti-       °  ',        ^  .       ^   .  ^  -,■      ■  n 

faciens  or  Ergot,  ordcr  has  uecn  noticed  m  two  distinct  lorms — 
(After  Hassan.)  ^|-^g  ^^^  ^  nci'vous  discasc,  characterized  by 
spasmodic  convulsions ;  and  the  other,  which  is  known  in 
Prance  as  gangrenous  ergotism,  and  in  Germany  as  the 
creeping  sickness.  The  symptoms  of  each  form  are  well 
described  in  Christison's  work  on  Poisons. 


INSPECTION    AND    EXAMINATION    OF    COEN  491 

There  are  two  chemical  tests  for  ergot — the  first  by 
Laneau,  and  the  second  by  Wittstein. 

Make  a  paste  of  the  flour  with  a  weak  alkali ;  add 
dilute  nitric  acid  to  slight  excess,  and  then  neutralize 
with  an  alkali,  when  a  violet  red  colour  is  produced  if 
ergot  be  present,  which  becomes  rosy  red  when  more 
nitric  acid  is  added,  and  violet  when  an  alkali  is  intro- 
duced. 

The  second  test  for  ergot  is  to  add  liquor  potassse  to 
the  flour,  which  develops  a  herring-like  smell  if  it  contains 
ergot. 

Smut  or  Dust  Brand  {Ustilago  segetum)  is  a  fungus "Smut.' 
that  exhibits  a  partiality  for  barley  and  oats. 


Fio.  85. — Ustilago  segetum,  x  420  diam.  Fia.  86.— Tilletia  caries,  x  420  diam. 

Bunt  or  Pepper  Brand  {Tilletia  caries)  is  a  fungus  only  Bunt  or 
met  with  in  wheat  grains.  It  is  developed  at  the^''^'^*^' 
expense  of  the  seeds  in  the  form  of  spores  resembling 
a  fine  dust.  The  spores  are  about  "0007  of  an  inch  in 
diameter.  As  its  name  indicates,  it  possesses  a  dis- 
gusting smell,  whilst  the  powder  of  "  Smut "  is  inodorous. 
It  is  questionable  whether  or  not  the  consumption  of 
flour  containing  this  fungus  is  deleterious  to  health. 
It  is  chiefly  employed  in  the  manufacture  of  ginger- 
bread. 


492 


INSPECTION    AND    EXAMINATION    OF    CORN 


Rust. 


Rust  (Puccinia  graminis). — This  fungus  infests  the 
chaff,  stem,  and  leaf  In  its  young  state  it  was  formerly 
know  under  the  name  of  Ureclo  riibigo  and  linearis. 


CHAPTEE   XLVIII 

INSPECTION   AND    EXAMINATION    OF    FLOUR 

In  the  inspection  of  flour  we  should  note   the   colour,  Physical 
smell,  taste,  and  feel,  for  we  may  then  receive  a  valu-*^  ^'^°  ^'^^' 
able  hint  as  to  its  wholesomeness  or  quality.     "Weevils 
(Calandra  granaria,  vide  fig.  82)  are  often  found  by  this 
rough  scrutiny. 

The  examination  of  flour  that  devolves  on  the  Medical  chemical 
Officer  of  Health  is  of  two  kinds:  chemical,  to  determine scopic!^'  " 
its  quality  and  the  presence  of  injurious  admixtures ;  and 
microscopic,  to  discover  adulterants  and  animal  parasites, 
which  are  often  found  in  damaged  flour. 

The  adulteration  of  wheaten  flour  with  that  of  cereals 
of  less  nutritive  value,  or  with  vegetables  that  are  deficient 
in  nitrogenous  principles,  may  be  considered  by  some  as 
one  of  fraud,  which  does  not  concern  a  guardian  of  the 
public  health. 

The  weakening  of  the  strength  of  the  "  staff  of  life," 
on  which  the  poor  man  has  principally  to  lean  for  the 
support  of  himself  and  family,  is  an  undoubted  injury  of 
very  serious  import.  The  substitution  of  fat-forming  for 
flesh-producing  principles  into  the  staple  article  of  diet 
cannot  but  be  regarded  as  a  wrong  that  is  calculated  to 
diminish  the  working  powers  of  labourers  of  all  classes. 

The  regulations  for  the  government  of  King  Henry 
VIII.'s  household  ordain  that  "his  hicrhness'  baker  shall 


494 


INSPECTION   AND    EXAMINATION    OF    FLOUR 


not  put  alum  in  the  bread,  or  mix  rye,  oaten,  or  bean 
flour  with  the  same,  and,  if  detected,  he  shall  be  put  in 
the  stocks."  The  use  of  alum  in  bread-making  was 
punishable  in  the  reign  of  George  IV.  by  a  fine  of  £20 
or  twelve  months  imprisonment. 

The  nutritive  value  of  the  different  farinaceous  articles 
of  food,  especially  of  those  with  which  flour  is  apt  to  be 
adulterated,  is  well  seen  in  Dr.  Letheby's  Table  of 
Analyses,  an  abridgment  of  which  may  be  usefully  inserted 
for  reference. 


NUTRITIVE  VALUES  IN  ONE  HUNDRED  PARTS. 


6 

c5 

Total  per  cent.  1 

Nutritive 

"^  rj, 

N 

Values  of  the 

.s" 

o 

rt 

^ 

A 

3 
o 

q  j; 

principal 

cS 

"3 

to 

3 

s 

c 

II 

Farinaceous 

^ 

.Q 

J 

m 

m 

t£) 
g 

cM 

Foods. 

< 

s 

2 

^    M 

rt  « 
o 

Bread 

37 

8-1 

47-4 

3-6 

1-6 

2-3 

8-1 

55-00 

Wheat  flour 

15 

10-8 

66-3 

4-2 

2-0 

1-7 

10-8 

75-50 

Barley  meal 

1 

6-3 

69-4 

4-9 

2-4 

2-0 

6-3 

80-30 

Oatmeal    . 

15 

12-6 

58-4 

5-4 

5-6 

3-0 

12'6 

77-80 

Rj'e  meal . 

15 

8-0 

69-5 

3-7 

2-0 

1-8 

8-0 

78-20 

Indian  meal 

14 

11-1 

64-7 

0-4 

8-1 

1-7 

IM 

85-35 

Rice     .     . 

13 

6-3 

79-1 

0-4 

0-7 

0-5 

6-3 

81-25 

Peas 

15 

23-0 

55-4 

2-0 

2-1 

2-5 

23-0 

62-65 

Arro'RToot 

18 

82-0 

82-00 

Potatoes    . 

75 

2'l 

18-8 

3-2 

6 -2 

0-7 

2i 

22-50 

Carrots 

83 

1-3 

8-4 

6-1 

0-2 

1-0 

1-3 

15-00 

Parsnips   . 

82 

1-1 

9-6 

5-8 

0-5 

1-0 

1-1 

16-65 

Turnips     .     . 

91 

1-2 

5-1 

2-1 

0-6 

1-2 

7-20 

If  wheaten  flour  is  made  by  grin  ding  together  the 
whole  of  the  grain,  it  contains  more  flesh-forming  material 
than  any  other  of  the  cereals,  sometimes  reaching  to  22 
per  cent.  The  finer  the  flour  the  less  of  nitrogenous 
matters,  of  fat  and  of  mineral  matters,  and  the  more  of 
starch.  The  most  nutritious  portions  of  the  grain  are 
the  outer  or  coarser  which,  containing  a  larger  proportion 
of  cellular  fibre  and  woody  matter,  are  less  easily  digested 


INSPECTION    AND    EXAMINATION    OF    FLOUR 


495 


by  persons  of  weakly  constitution.  Bread  and  puddings 
made  of  whole  meal  flour  are  highly  nourishing,  if  they 
can  be  easily  digested,  and  do  not  exert  a  too  great 
laxative  influence  on  the  intestines  through  the  mechanical 
irritation  of  the  small  portions  of  husk  or  bran. 

The  most  distinguished  dentists  of  the  day  tell  us  caries  of 
that  one  great  cause  of  the  caries  of  teeth  is  the  substi- 
tution of  the  fine  and  delicately  prepared  for  the  coarser 
and  rougher  foods  that  belonged  to  a  former  and  less 
civilized  state  of  society.  Whole  meal  bread,  potatoes 
undeprived  of  their  skins,  etc.,  etc.,  are  suggested  as  pre- 
ferable. Whether  or  not  such  coarse  foods  act  beneficially 
on  the  teeth  in  a  mechanical  manner  by  scouring  them, 
and  so  preventing  accumulations  of  food  and  tartar,  does 
not  transpire. 

Chemical  Exa^niination. 

The  unsoundness  of  flour  is  shown  by  the  amount  of 
water,  ash,  sugar,  dextrine,  gum,  and  gluten,  etc. 

Wanklyn's  analysis  of  fine  wheaten  flour  is  as 
follows : — 


"Water 

Ash  .  .  . 

Fat  .  .  . 

Sugar,  Gum,  and  Dextrine  . 

Albuminous  matters  (Gluten,  etc.^ 

Starcli 


16 

5 

0 

74 

1 

2 

3 

3 

12 

0 

66 

3 

100 

0 

Water. — Place    a    little   flour   in   a   small   platinum  Amount  of 
dish  (such  as  is  employed  for  obtaining  milk  residues)  ™°^^*'^''^" 
of  known  weight,  and  weigh  it.      Place  the   dish  thus 
charged  over  a  hot  water  bath  for  one  hour  and  a  half 
to    drive   off   moisture.     Weigh    and    then    replace    the 
dish  on  the  bath,  and  after  the  interval  of  half  an  hour 


496  INSPECTION   AND    EXAMINATION    OF    FLOUK 

again  weigh.     The   object   of  weighing  twice   is   to   be 
sure  that  all  water  is  expelled.     For  example  : — 

Sample  of  flour  and  dish    .  .  .  9*959 

Platimun  dish        .  .  .  .  7  "9  7  8 


Weight  of  flour      ....  1-981 


After  Exposure  on  Hot  Water  Bath. 

1st  Weighing.  2d  Weighing 

Flour  and  dish      .  .  9-680         .  9-650 

Dish  .  .  .  7-978         .  7-978 


1-702  .  1-672 


To  obtain  percentage — 


Weight  of  flour  taken.       ^'^'S^*  ^^  of'moiltoe!''^''^''"'' 

1-981  :  1-672  :       :  100 

100 


l-981)167-200(84-4 
100  -  84-4  =  15-6  per  cent. 

Good  flour  contains  on  an  average  from  about  10  to 
1 6  per  cent  of  moisture.  The  more  water  that  is  present 
the  greater  the  liability  to  change,  and  the  less  nutriment 
in  a  given  weight.  Prof  Parkes  counselled  that  flour  con- 
taining over  18  per  cent  of  water  should  be  rejected. 
Weight  of  ^sA. — Burn  the  dried  contents  of  the  dish  by  applying 

^^^-  the  flame  of  a  Bunsen's  burner.     The  coke  formed  requires 

to  be  stirred  with  a  piece  of  thick  platinum  wire.  It  is 
at  length  reduced  to  an  ash,  which  should  be  weighed. 
Por  example : — 

Weight  of  ash  and  dish        .  8-035 

dish        .  .  7-978 


Weight  of  ash         .  '057 


INSPECTION    AND    EXAMINATION    OF    FLOUR  497 

Weight  of  flour  taken.  Weight  of  ash. 

1-981  :  -057  :      :  100 

100 


l-981)5-700(2-87 
Ash  2-87  per  cent. 

The  average  weight  of  ash  is  '7  to  '8  per  cent. 
Dr.  James  Bell  asserts  that  it  varies  from  '3  5  to  '86 
per  cent.      If  a  sample  of  wheaten  flour  yields  more  than 

1  per  cent  there  is  something  wrong  about  it,  and  the    ■ 
presence  of  a  mineral  is  suspected.      The  inorganic  sub- 
stances with  which  flour  is  most  commonly  adulterated 
are   carbonate   of   lime    or   magnesia,    sulphate   of   lime, 
silicate  of  magnesia,  bone  dust,  etc.      If  the  ash  exceeds 

2  per    cent,    add   hydrochloric   acid.      If  distinct    effer- 
vescence is  produced,  chalk  has  been  probably  added. 

To  detect  mineral  substances  shake  a  known  quantity 
of  flour  with  chloroform  in  a  burette.  The  flour  floats 
and  inorganic  bodies  subside,  which  may  be  drawn  off  by 
the  tap,  dried  by  a  gentle  heat,  and  weighed.  The  ash  of 
flour  consisting  of  ground  leguminous  seeds  is  heavier 
than  that  of  wheat-flour,  and  is  strongly  alkaline. 

The  ash  of  flour  is  composed  mainly  of  the  three 
phosphates  of  potash,  magnesia,  and  lime. 

The  ash  of  pure  oatmeal  does  not  exceed  2 "3  6  per 
cent. 

Alum  is  sometimes  purposely  mixed  with  flour  before  Aium. 
it  is  made  into  bread.  It  may  be  detected  by  the  log- 
wood test  {vide  page  517),  but  if  the  characteristic  colour 
reaction  is  not  obtained  with  this  test,  Mr.  W.  C.  Young 
advises^  that  the  flour  should  be  made  into  a  paste  with 
boiling  water  before  applying  the  ammoniacal  logwood 
tincture,  when,  if  alum  is  present,  a  bluish-gray  colour 
is  developed  permanent  for  a  week.      An  approximative 

^  Analyst,  January  1879. 
2  K 


498  INSPECTION    AND    EXAMINATION    OF    FLOUR 

estimate  of  the  quantity  of  alum  may  be  determined,  by 
making  comparative  experiments  as  to  the  depth  of  the 
bluish  colour  with  pure  flour,  made  into  an  emulsion,  to 
which  different  known  quantities  of  a  standard  solution 
of  alum  in  water  (1  gramme  to  the  litre)  have  been  added. 
Sugar, Dex-  SugciT,  Dextrine,  and  Gtivi. — Weigh  out  100  grammes 
Gum.  "'  of  flour,  and,  having  placed  it  in  a  large  porcelain 
evaporating  dish,  introduce  some  water,  and  mix  the 
water  and  flour  thoroughly  together  with  the  fingers,  so 
as  to  ensure  the  complete  admixture  of  every  particle  of 
the  flour  with  the  water.  This  semifluid  mixture  is 
poured  into  a  half-litre  flask,  and  water  is  added  until 
the  mark  is  reached  denoting  that  quantity.  The 
contents  of  the  flask  are  filtered.  After  rejecting  the 
first  portions  of  the  filtrate,  50  c.  c.  of  the  filtrate  are 
collected  and  evaporated  to  dryness  in  a  platinum  dish 
of  known  weight  on  a  water  bath. 

WeigM  of  clisli  and  substance  after  evaporation      2 6  "8 7 5 
dish  ....  26-210 


■665 

As  a  tenth  (50  c.  c.)  of  the  500  c.  c.  (half-litre)  which 
contained  the  100  grammes  of  flour  was  taken,  it  is 
necessary  to  multiply  by  10  to  obtain  the  percentage : 
•665  X  10  =  6"65  per  cent. 

A  cold  aqueous  extract  should  not  exceed  4-7  per  cent. 

The  Albumi7ious  principles  are  divided  into  those 
which  are  soluble  and  those  which  are  insoluble  in  cold 
water.  The  former,  which  include  vegetable  albumen, 
are  calculated  in  the  last-described  estimate  of  the  cold 
water  extract.  The  latter  are  known  under  the  name 
Gluten.  of  glutcu,  a  mixturc,  according  to  Eitthausen,  of  giiadin, 
gluten-casein,  gluten-flbrin,  and  mucedin. 

Place    100    grammes    or    100    grains    in    a    Berlin 


INSPECTION   AND    EXAMINATION    OF    FLOUR  499 

evaporating  disli,  and  mix  it  thoroughly  with  a  little 
water,  so  as  to  make  a  dough.  Add  water  to  it,  mean- 
time kneading  it  well  with  the  fingers.  Pour  off  the 
water  and  add  fresh.  This  addition  and  removal  of 
water  is  carried  on  until  the  water  ceases  to  be  milky 
in  appearance,  when,  all  starch  having  been  thus  re- 
moved, only  a  tenacious  mass  of  gluten  remains,  which 
is  to  be  dried  on  the  water  bath  and  weighed. 

Good  flour  contains  from  8  to  12  per  cent  of  gluten. 
Prof  Parkes  says  that  flour  should  be  rejected  in  which  it 
falls  below  8  per  cent. 

Accidental  and  intentional  admixtures  of  arsenic  with  Metallic 
flour  sometimes,  but  rarely,  occur.    I  have  only  encountered 
one  case  although  I  have  been  in  the  profession  nearly 
thirty  years. 

A  remarkable  case  of  an  outbreak  of  lead  poisoning, 
in  which  between  fifteen  and  twenty  persons  were 
simultaneously  affected,  has  recently  been  published  by 
Dr.  Alford.-^  It  was  traced  to  the  admixture  of  lead 
with  the  flour  in  the  process  of  grinding  the  corn.  The 
millstone  being  of  a  very  loose  nature,  large  spaces 
existed  in  it,  which  had  been  filled  up  by  pouring  into 
them  quantities  of  molten  lead.  There  were  ten  pounds 
of  lead  upon  the  surface  of  the  millstone,  and  the  cavi- 
ties were  all  filled  with  the  same  metal.  The  tests 
described  in  the  foregoing  pages  are  sufficient  to  identify 
either  of  these  poisons  as  they  occur  in  flour. 


Microscopic  Examination. 

The  flour  of  diseased  corn  is  often  seen  to  contain  the 
spores  of  fungi  {vide  page  490). 

The  most  common  animal  found  in  flour  that  has  been 

1  Sanitary  Record,  May  25,  1877,  p.  321. 


500 


INSPECTION    AND    EXAMINATION    OF    FLOUR 


kept  in  a  damp  place,  or  been  otherwise  damaged,  is  the 
Acarus  farince  which  multiplies  with  great  rapidity. 


The  Acarus 
Faring. 


Wheat 
Starch 


Barley 
Starch. 


Fig  88. — Acarus  Farinse,  x  85  diam.    (After  Parkes.) 

Barley-meal,  beans,  potato,  maize,  oat,  rye,  and  rice 
are  the  most  common  adulterants  of 
wheat  flour,  which  may  all  be  detected 
by  the  microscope. 

1.  Barley. — The    starch  granules   of 
barley  so  closely  resemble  those  of  wheat 
that  they  cannot  readily  be  distinguished 
Fig.  89.    Wheat  starch  £j,y^  ^^^  another.     Barlcv  starch  consists 

X  420  diam.      (After  '^ 

Cameron.)  rather   of  small  and  large  grains,  with 

very  few  of  an  intermediate  size;  whereas  this  peculiarity 
does  not  exist  in  the  case  of  wheat  starch. 

When   mingled    together,   as   in   the   adulteration   of 
wheat    with    barley,    it    is    thus    almost    impossible    to 


INSPECTION    AND    EXAMINATION    OF    FLOUR  501 

distinguish  the  two  starches.      As  the  finest  flour  con- 


Testa  of 

Wheat. 


Fig.  90.— Testa  of  Wheat,  x  200.    (After  Hassall.) 

Transverse  Section  of  Testa  of  Wheat  Grain. — d.  Cells  of  substance  of  grain  containing 
starch  granules.    The  testa  consists  of  3  coats,  2  longitudinal  and  1  transverse. 
Longitndinal  Coat — Outer  Layer. — Margins  of  cells,  distinctly  beaded. 
Transverse  Coat. — Margins  of  cells,  beaded,  but  to  a  less  extent. 
Longitudinal  Cells  of  Surface  of  Grain=c.  consists  of  only  1  layer. 

tains  portions  of  the  investing  membranes  of  the  grain, 
the  presence  of  barley  meal  is  diagnosed'  by  an  examina- 


Testa  of 
Barley. 


Fig.  91.— Testa  of  Barley,  x  200.    (After  Hassall.) 

Transverse  Section  of  Testa  of  Barley  Grain. — The  cells  of  substance  of  grain  containing 
starch  granules  are  not  here  depicted.  The  testa  consists  of  4  coats,  3  longitudinal  and 
1  transverse.  - 

Longitudinal  Coat — Outer  Layer. — Margins  of  cells  not  beaded,  but  slightly  waved. 

Transverse  Coat. — Margins  of  cells  not  beaded  or  waved. 

Longitudinal  Cells  of  Surface  ofGrain  =  c.  consists  of  3  layers. 


tion  of  portions  of  the  testa,  which  should  be  sought  for. 


502 


INSPECTION   AND    EXAMINATION    OF    FLOUR 


The  cells  of  tlie  substance  of  the  grain  of  barley  are 
seen  when  emptied  of  starch  to  be  of  more  delicate 
structure  than  those  of  wheat,  and  to  present  a  fibrous 
appearance. 
Bean  starch.  2.  Bccin  cincl  PecL — The  addition  of  bean  and  pea 
meal  can  easily  be  detected  by  a  microscopic  examination. 


Fig.  92.— Bean  Starch.    (After  Parkes.) 

If  a   little   boiling  water   be   thrown   on   flour   thus 


Fig.  P3.— Potato  Starch  not  polarized,  x  285.    (After  Parkes.) 

adulterated,  the  characteristic  smell  of  beans  and  peas  is 
evolved. 


INSPECTION    AND    EXAMINATION    OF    FLOUR 


50; 


Starch. 


Donne's  test  consists  in  pouring  successively  a  little 
nitric  acid  and  ammonia  on  the  flour.  If  it  is  not 
adulterated  with  beans,  no  marked  reaction  is  apparent ; 
but  if  bean  meal  is  present  a  deep  red  colour  is  observed. 
Lassaigne  suggests  the  addition  of  a  solution  of  an  iron 
salt,  which  gives  to  pure  flour  a  pale  straw  colour,  but  to 
a  mixture  of  beans  and  flour  shades  ranging  from  orange 
to  dark  green. 

3.  Potatoes. — If  potato  starch  is  found  in  flour,  the  Potato 
admixture  is  as  much  a  fraud  as  the  dilution  of  milk' 
with  water.  The  pyriform 
appearance  and  eccentric 
hilum  are  characteristics  of 
this  starch.  It  is  well  to 
add  a  drop  of  weak  liq. 
potassce,  when  examining 
flour  under  the  microscope, 
for  this  re-agent  swells  up 
potato  starch  granules  en- 
ormously, and  has  very 
little  effect  on  those  of 
wheat  starch.      Chevallier's 

.  Fia.  94.— Potato  starch  polarized,  X  200. 

method  is  a  good  one,  and 

is  thus  described  by  Mr.  Wynter  Blyth:^  "  Equal  weights  of 
flour  and  sand  are  to  be  triturated  with  water  until  a  homo- 
genous paste  is  formed,  which  is  then  diluted  and  filtered  ; 
to  the  filtrate  is  added  a  freshly-prepared  solution  of 
iodine,  made  by  digesting  for  about  10  minutes  3 
grammes  of  iodine  in  60  c.  c.  of  water,  and  then  decanting. 
If  the  flour  is  pure,  this  addition  will  give  a  pink  colour, 
gradually  disappearing ;  whilst  if  potato  starch  should  be 
present,  the  colour  is  of  a  dark  purple,  only  disappearing 
gradually.  By  comparing  the  reaction  with  flour  known  to 
be  pure,  this  difference  of  behaviour  is  readily  appreciated." 

^  Foods — Composition  and  Analysis. 


504 


INSPECTION    AND    EXAMINATION    OF    FLOUR 


Maize 
Starch. 


4.  Maize. — The  starch  granules  on  the  outer  part  of 


Fig.  95.- 


X250 
-Maize  Starch. 


Oat  Starch. 


Adultera- 
tion of 
oatmeal. 


(After  Parkes.) 

the  grain  are  of  hexagonal,  and  in  the  centre  of  a  spherical 
or  oval  form. 

5.  Oats. — The  granules  of  oat  starch,  unlike  those  of 
the  other  starches,  do  not  exhibit  the 
black  characteristic  crosses  under  the 
influence  of  polarized  light.  As  oats  is 
a  very  highly  nitrogenous  material,  the 
admixture  of  a  little  oatmeal,  with  other 
farinaceous  foods,  cannot  be  objected  to 
Fig.  96.-oat  starch,  X  OH  Sanitary  grouuds. 

420.  (After  Cameron.)  Oatmeal  coutaius  more  fatty  matters 
than  wheaten  flour.  Wliere,  as  in  Scotland,  oatmeal,  to  a 
very  large  extent,  takes  the  place  of  wheaten  flour,  the 
toning  down  or  weakening  of  oatmeal  with  the  less 
nutritive  barley  meal,  is  a  practice  which  is  much  to  be 
objected    to.-^     The    microscope   shows    the    presence   of 

^  Conviction  for  adulterating  oatmeal  with  from  25  per  cent  to  3.5  per 
cent  of  barley  meal. — Sanitary  Record,  January  20,  1877,  p.  42. 


INSPECTION  AND  exa:.:ixation  of  flour        505 

starch  granules,  which  may  be  either  wheat  or  barley. 
As  wheat  is  not  employed  as  an  adulterant,  the  granules 
will  almost  certainly  be  those  of  barley.-^  It  is  asserted 
that  retail  dealers  mix  barley  meal  with  the  somewhat 
buff-coloured  oatmeal,  to  impart  a  white  and  cleaner  hue. 
The  presence  of  about  1  per  cent  of  barley  in  oatmeal 
may  be  charitably  looked  upon  as  accidental,  but  as 
much  as  5  per  cent  must  be  regarded  as  a  fraud. 

As  a  mode  of  estimating  the  percentage  of  barley  in 
oatmeal  that  is  adulterated  with  it,  Dr.  Muter  suggests 
the  measurement  of  the  starch  granules  by  the  aid  of  a 
-^Q  inch  objective,  and  a  "  B  "  micrometer  eyepiece.  Oat 
granules  measure  "00037  inch.  Barley  granules  measure 
•00073  inch,  and  a  few  of  them  four  times  this  size, 
namely -00292  inch.  He  writes:^  "The  best  criterion 
to  go  on  for  the  estimation  of  the  percentage  is  the 
number  of  granules  measuring  '00292  inch,  which  are 
found  in  barley  to  bear  a  very  constant  relation  to  the 
•00073  inch  granules." 

6.  Hye. — The    peculiar    rayed    hilum  of   rye    starch  Rye  starch, 
serves  to  distinguish  it  from  any  other. 


Fig.  97.— Bye  Starch,  x  420.  (After  Fig.  98.— Rice  Starch,  x  420.  (After 

Cameron.)  Cameron.) 

7.  Bice. — Eice   meal   is   sometimes   adulterated  with  Rice  starch. 
lime,  which  can  easily  be  detected  with  hydrochloric  acid. 
A  large  quantity  was  seized  in  Liverpool  in  1879  which 

^  English  barley  is  of  course  dearer,  but  foreign  barley  is  cheaper, 
than  oats. 

2  Analyst,  January  31,  1877,  p.  190. 


506 


INSPECTION    AND    EXAMINATION    OF   FLOUR 


Darnel 
Grass. 


contained  from  40  to  50  per  cent  of  powdered  marble. 
Inferior  rice  is  sometimes  fraudulently  mixed  with 
wlieaten  flour  to  render  bread  whiter  and  heavier,  for  rice 
retains  much  moisture. 

Loliuvi  temulentum,  or  Darnel  Grass. — The  seeds  of 
this  grass  are  apt  to  become  accidentally  or  fraudulently 
mixed  and  ground  with  the  grains  of  wheat.  As  the  seed 
contains  a  poison  of  the  acro-narcotic  class,  it  is  necessary 
to  be  able  to  diagnose  the  dangerous  admixture.  Giddi- 
ness, tremor,  convulsions,  and  vomiting  are  the  symptoms 
commonly  produced  by  eating  bread  containing  the  flour 
of  darnel  grass.  Many  accidents  from  consuming  flour 
thus  poisoned  are  recorded.^  In  the  well-known  case  of 
poisoning  at  the  Cologne  prison,  in  which  sixty  persons 
were  affected,  one  and  a  half  drachms  of  darnel  were 
found  in  every  six  ounces  of  the  flour.  The  starch 
granules  of  the  darnel  closely  resemble  those  of  oats,  but 
the  difference  in  the  appearance  of  the  testa  of  the  two 
grains  is  very  striking. 


Fig.  99.— Testa  of  Oat  Grain,  x  200 
diam.  a,  outer  ;  6,  middle  ;  c,  inner 
coats.  (After  Hassall.) 


Fig.  100. — Testa  of  Lolium  temulentum 
(Darnel)  Grain,  x  200.  (After  Hassall.) 


Pure  flour,  when  mixed  with  alcohol,  forms  a  straw- 
coloured  solution,  which  possesses  an  agreeable  taste. 
Flour  which  contains  darnel  is  said  to  give  a  greenish 
solution,   with    a  disagreeable    repulsive    taste,   and   on 

^  London  Medical  and  Physiological  Journal,  xxviii.   182  ;  Buchner's 
Toxikologie,  174  ;  Annalen  der  Phannacie,  xvi.  318. 


INSPECTION    AND    EXAMINATION    OF    FLOUR  507 

evaporation  a  resinous  yellow-green  extract  is  left 
(Parkes). 

If  some  difficulty  is  experienced  in  forming  an  opinion, 
the  physiological  test  of  administering  a  small  quantity  to 
a  dog,  and  noticing  the  effect,  is  admissible.  Some  rare 
cases  of  poisoning  have  occurred  from  the  mixture  with 
flour  of  vetches  named  Lathyrus  sativus,  and  cicera,  and 
of  the  pollen  of  the  male  catkin  of  the  hazel. 

If,  whilst  inspecting  a  specimen  of  flour  with  the 
microscope,  particles  possessing  a  resemblance  to  fragments 
of  bone  are  noticed,  the  appearance  of  which,  when  magni- 
fied, is  well  known  to  every  medical  man,  a  drop  of  a 
solution  of  nitrate  of  silver  should  be  added,  and  the  flour 
again  examined  by  the  microscope.  If  these  minute 
objects  really  consist  of  bone  dust,  they  will  become 
yellow  under  the  influence  of  this  reagent. 


CHAPTEE   XLIX 

INSPECTION    AND    EXAMINATION    OF    BREAD 

An  inspection  of  bread  will  often  afford  many  suggest- 
ive hints  as  to  its  condition.  It  is  quite  unnecessary 
to  describe  the  appearance,  taste,  and  smell  of  good  bread, 
for  every  one  is  familiar  with  it.  How  few,  however, 
have  any  notion  as  to  the  unwholesome  manner  in  which 
the  greater  part  of  the  bread  that  is  eaten  is  manufactured. 
Pure  bread  is  rarely  procurable  in  our  towns  and  cities, 
under  the  present  system  that  prevails  of  "  flesh  dough- 
kneading."  The  cellars  employed  as  bakehouses  in 
London  and  other  cities  are  generally  filthy  places,  with 
drain  smells,  infested  with  beetles,  mice,  and  rats,  which 
make  playful  incursions  into  the  kneading-trough  and 
Mode  of  flour-sack.  The  work  of  kneading  is  so  laborious  as  to 
manufactur-  excitc  profuse  pcrspiratiou,  which  drops  into  the  dough. 

mg  our  daily  ^  ^         -^  , 

bread.  The  flour  rises  in  clouds,  and  the  workers  begin  to  cough 
and  sneeze.  When  the  process  is  almost  finished,  the 
dough  adhering  to  their  arms  is  scraped  off,  and  the  flour 
that  has  settled  on  their  hair  is  brushed  off  with  a  coarse 
brush  into  the  kneading-trough.  Thus  cast-off  epithelium 
from  the  skin,  hairs,  head  scurf,  nasal  and  pulmonary 
excretions  of  men,  the  majority  of  whom  are  dirty  and 
unhealthy,  are  mingled  with  the  dough  that  forms  our 
daily  bread.  Fifteen  years  ago  these  revolting  disclosures 
were  made  djoro^os  of  the  grievances  of  journeymen  bakers. 


INSPECTION    AND    EXAMINATION    OF    BEEAD  509 

and  are  to  be  found  in  Government  Blue  Books.-^  Not- 
withstanding the  publicity  given  to  these  facts,  the  manu- 
facture of  nearly  all  bread  is  carried  on  at  the  present 
time  in  the  same  disgusting  way.^  Forgetfulness  would 
appear  to  be  bliss  no  less  than  ignorance.  As  guardians 
of  the  public  health,  it  behoves  medical  officers,  not 
only  in  the  interest  of  the  journeymen  bakers  them- 
selves, whose  lives  are  so  terribly  shortened  by  their  un- 
wholesome avocation,  but  in  that  of  the  public  at  large 
who  are  supplied  with  foul  bread,  to  bring  abou.t  the 
employment  of  machine-made  bread.  Bread  can — now 
that  many  mechanical  dough -kneading  and  mixing 
machines  of  different  kinds  exist,  and  the  dough  can  be 
baked  by  gas,  hot  air,  or  steam,  with  a  complete  absence 
of  smoke,  dust,  or  sulphur  fumes — be  manufactured  so  that 
the  human  hand  never  touches  it,  and  so  that  the  bakers 
shall  not  receive  any  injury  to  their  health. 

Microscopic  Examination. 

The  presence  of  fungi  in  bread,  such  as  the  several 
varieties  of  Fenicillium  or  common  mildew,  which  gives  a 
greenish  or  brownish  or  reddish  hue  in  patches,  or  the 
Oidium  orantiacum  which  is  distinguished  by  yellow  spots, 
shows  that  it  is  unfit  for  human  food,  for  there  is  good 
reason  to  believe  that  illness  has  been  produced  by  such 
bread. 

As  cooking  so  greatly  alters  the  appearance  of  starch 
granules,  the  flour  from  which  the  bread  is  made  should 
be  examined. 

Adulterations  of  Bread. 

The  most  common  adulterants  of  Bread  are — 
Alum. 

^   Vide  Report  of  H.M.   Special  Commissioner,   H.   S.  Tremenheere, 
Esq.,  C.B.,  to  the  Secretary  of  State  of  the  Home  Department. 
2  Vide  Medical  Examiner,  July  12,  1877  and  July  19,  1877. 


510  INSPECTION    AND    EXAMINATION    OF    BREAD 

Terra  alba  (hydrated  sulphate  of  lime)  and  whit- 
ing (fine  carbonate  of  lime),  carbonate  and  sili- 
cate of  magnesia. 

Sand. 

Sulphate  of  copper. 

Eice. 

Potatoes. 
Alum.  1.   Alum. — If   the   grain   of   wheat   is   subjected    to 

warmth  and  moisture — as,  for  example,  from  long  expo- 
sure in  the  field,  or  from  storage  in  warm,  damp  granaries 
— a  certam  degTee  of  germination  occurs,  an  action  which 
is  accompanied  by  the  conversion  of  the  albuminous 
matters  into  diastase  (a  substance  that  changes  part  of 
the  starch  into  dextrine),  and  a  saccharine  body  called 
glucose.  In  the  manufacture  of  bread  from  this  damaged 
or  partially  fermented  flour,  a  larger  quantity  of  sugar  is 
formed  from  the  starch  under  the  influence  on  it  of  the 
diastase  than  is  desirable,  a  sweetish,  unpleasant,  dark- 
coloured  loaf  being  the  result. 

Alum,  if  added  to  damaged  flour,  checks  the  action  of 
the  diastase  on  the  starch,  and  thus  prevents  its  conver- 
sion into  dextrine  and  sugar,  at  the  same  time  improving 
the  colour  of  the  bread. 

Damaged  flour  being  apt  to  create  dyspepsia  and 
diarrhoea,  this  astringent  salt  is  found  to  neutralize  to 
some  extent  these  ill  effects.  The  scoundrels  who  thus 
swindle  the  public  by  passing  off  as  a  superior  food  of 
the  first  quality,  at  a  high  price,  an  unwholesome  and 
inferior  doctored  article,  are  happily  amenable  to  the 
law.  One  unfortunate  stumbling-block  in  the  way  of 
preventing  this  extensive  system  of  fraud,  which  is  so 
injurious  to  that  part  of  the  community  that  depends  so 
largely  for  its  sustenance  on  bread — namely,  the  agricul- 
tural labourer — has  been  the  difference  of  opinion  amongst 
scientific  men  as  to  whether  or  not  alum  is  injurious  to 


INSPECTION    AND    EXAMINATION    OF    BREAD  511 

health  in  the  quantities  in  which  it  is  generally  detected 
in  bread.  The  view  that  prevails  amongst  physicians  is 
that  a  daily  dose  of  alum,  even  if  in  minute  quantities,  is 
not  by  any  means  conducive  but  rather  deleterious  to 
health.  Dr.  Dauglish  holds  that  the  efficacy  of  alum  in 
the  prevention  of  the  solution  and  decomposition  of  starch 
in  the  loaf  is  more  or  less  continued  in  the  stomach ;  for 
the  alum,  whilst  neutralizing  the  action  of  the  diastase, 
will  further  neutralize  the  influence  of  the  gastric  juices, 
the  result  being  imperfect  digestion,  with  the  consequent 
elimination  from  the  system  of  substances  which  should 
otherwise  meet  with  ready  assimilation  as  true  food,  in- 
cluding a  large  proportion  of  gluten  and  unaltered  starch.-^ 
Many  scientific  chemists,  who  have  but  a  smattering  of 
medical  knowledge,  consider  that  alum  in  bread  is  harm- 
less, except  perhaps  when  present  in  large  amount.  In 
many  districts,  where  the  only  water  obtainable  is  muddy, 
it  is  the  practice  to  place  a  pinch  of  alum  in  a  large  butt 
of  water  to  clarify  it  by  a  precipitation  of  the  suspended 
impurities.  The  men  in  such  parts  drink  nothing  but 
beer.  I  have  never  seen  amongst  the  wives  of  these  men 
who  drink  such  water  a  perfectly  healthy  woman. 

2.   Terra  Alba  {Hydrated  Sulphate  of  Lime  =z  Plaster  o/"  sulphate 
Paris)  and    Whiting  {Garhonate  of  Lime),  Carbonate  and  carbonate 
Silicate  of  Magnesia. — The  presence  of  these  and  other  °f  i^™^' 

Carbonate 

mineral  substances  in  bread  is  suspected  if  the  ash,  which  and  silicate 
should  not  exceed  2  per  cent,  is  excessive.  They  are  °^  ^^enesia. 
added  to  increase  the  weight.  The  flour  from  which  the 
bread  has  been  made  should,  if  possible,  be  procured,  for 
flour  can  be  reduced  to  ash  far  more  rapidly  than  bread. 
Care  should  be  taken  not  to  mistake  the  coke  for  the  ash. 
Ee-ignition  will  diminish  the  weight  of  the  coke,  but  not 
that   of  the   ash.     The  Medical   Officer  of  Health  and 

^  "  Bread  and  Bread  Stuffs,"  by  B.  Dyer. — Sanitary  Record,  December 
14,  1877. 


512.         INSPECTION    AND    EXAMINATION    OF    BEEAD 

Analyst  of  the  City  of  London  seized,  in  January  1879,  a 
large  quantity  of  ilour  wliicli  consisted  of  as  much  as  7  0 
per  cent  of  plaster  of  Paris.  There  are  several  mills  in 
the  United  States  that  grind  white  stone  into  a  powder, 
sold  at  ^  cent  per  lb,  of  three  different  degTees  of  coarse- 
ness— "the  soda  grade,  sugar  grade,  and  flour  grade" — for 
purposes  of  adulteration.  The  prompt  action  of  the  Eussian 
Government  during  the  Eusso-Turkish  campaign,  on  dis- 
covering that  the  flour  furnished  by  the  head  of  the  Commis- 
sariat Department  contained  a  large  percentage  of  terra  alba, 
is  to  be  commended.  The  man  who  endangered  the  success 
of  the  enterprise  was  immediately  shot  for  his  dishonesty. 
Sand.  3.  Sand. — The  admixture  of  sand  with  bread  is  easily 

shown  by  the  silica  determination.  The  average  amount 
of  silica  in  good  bread  is  about  '025  per  cent. 
Sulphate  of  4.  Sulphate  of  Copper  is  used  by  bakers  on  the  Con- 
°^^^'^'  tinent  in  small  quantities  to  give  a  white  colour  and 
otherwise  improve  the  appearance  of  bread  manufactured 
from  damaged  flour.  The  continual  use  of  bread  thus 
adulterated  cannot  fail  to  be  injurious  to  health,  whatever 
the  quantity  of  the  poison  may  be. 

Modes  of  Detection. — 1.   Cut  a  smooth  slice  of  bread 

and  draw  across  its  surface  a  glass  rod  dipped  in 

a  solution  of  ferrocyanide  of  potassium.     If  copper 

be  present,  the  streak  will  be  of  a  brownish-red 

colour. 

2.   Burn  a  quantity  of  bread  (or  flour,  if  it  is  desirable 

to  test  it)  to  an  ash.      Boil  the  ash  in  a  platinum 

crucible  with   a  few   drops    of  strong  sulphuric 

acid,   which   should  afterwards   be  diluted  with 

water.      Place  in  the  solution  a  piece  of  zinc.     If 

copper  be  present,  it  will  be  deposited  on  the 

surface  of  the  platinum. 

Potatoes.  5.   Potatoes  are  generally  added  wdien  they  are  cheap, 

in  a  mashed  form,  to  dilute  the  flour  and  render  bread 


INSPECTION    AND    EXAMINATION    OF    BREAD  513 

heavier,  for  they  contain  between  70  and  80  per  cent  of 
water.  Bread  thus  adulterated  has  a  damp  apjoearance 
and  taste.  Many  housewives  add  a  few  boiled  potatoes 
to  the  flour  in  making  their  bread,  with  a  view  to  prevent 
the  bread  from  soon  becoming  dry. 

Mode  of  Detection. — Make  a  solution  of  bread.  Test 
it  with  red  litmus  paper.  If  it  is  not  alkaline,  burn  some 
of  the  bread,  and  test  the  ash  with  litmus  paper.  If  the 
ash,  instead  of  being  neutral,  is  alkaline,  potatoes  are 
probably  present.  The  percentage  of  water  in  the  bread 
and  its  appearance  must  also  be  noted. 

6.  Rice  is  added  to  bread  to  whiten  it  and  to  render  it  Rice, 
heavier,  as  it  contains  a  large  quantity  of  water. 

Ifode  of  Detection. — The  ash  of  rice  is  necessarily  low, 
namely  "85  per  cent.  An  excessive  percentage  of  mois- 
ture, an  unnatural  whiteness  of  the  bread,  and  a  low  ash, 
are  suggestive  of  this  adulteration.  The  flour  with 
which  the  bread  is  made  should  be  examined  microscopi- 
cally, for  the  granules  of  rice  are  different  from  those  of 
any  other  starch. 

Chemical  Examination. 

Water. — The  mean  amount  of  moisture  found  by  Dr.  water 
Odling  in  the  crumb  of  good  bread  was   43-4  per  cent,  ex«ed '^'^ 
the  maximum  of  all  the  25  specimens  exammed  yield- ^^°^*  ^^ 
ing  4 6 '7  per  cent  of  water. 

Place  a  small  portion  of  bread  in  a  platinum  dish  of 
known  weight.  Weigh.  Dry  over  water  bath  for  some 
time.  Weigh.  Expose  the  dish  on  tlie  water  bath  for 
another  half-hour,  and  again  weigh. 

Calculate  the  percentage.     For  example  : — 

Bread  and  dish     .  .  28-910 

Dish         .  .  .  26-205 


Weight  of  bread         .  2-705 

2  L 


514  INSPECTION    AND    EXAMINATION    OF   BREAD 

After  drying  at  212°  F. 


Bread  and  disli 

First 
■weighing. 

27-810 

Second 
■weighing. 

27-665 

Dish   . 

26-205 

26-205 

Weiglit  of  bread 

1-605 

1-460 

2-705  : 

1-460    :    : 

100 

100 

(53-97 

2-705) 

146-00000 

100-00 

53-97  of  solid. 

46-03  of  moisture. 

Result  46-03  per  cent  of  water. 

The  addition  of  mashed  potatoes  or  boiled  rice  (starchy- 
foods  that  are  deficient  in  the  nitrogenous  elements)  is  to 
be  suspected  if  the  percentage  of  water  is  excessive.  If 
bread  possesses  an  unnatural  whiteness,  and  no  alum  or 
terra  alba  can  be  detected,  rice  is  the  probable  adulterant. 
Ash  should  Ash. — Take  100  grammes  of  bread  (crust  and  crumb 
2°perc'ent.  i^  about  equal  proportions)  and,  having  cut  it  up  into 
fragments,  burn  it  in  a  Berlin  dish  of  about  5  inches  in 
diameter.  The  coke  that  forms  should  be  broken  up  by 
the  help  of  a  platinum  rod.  It  is  not  advisable  to  employ 
a  persistently  intense  heat,  as  there  is  a  danger  of  volatil- 
izing the  alumina  of  the  alum,  and  of  cracking  the  dish. 
When  the  cinder  and  ash  cease  to  glow,  and  when  they 
exhibit  a  gray  colour,  the  burning  may  be  considered 
complete.  The  ash  should  not  be  thoroughly  decarbonized 
for  fear  of  volatilizing  the  alumina.  The  burning  of  1 0  0 
grammes  of  bread  consumes  four  hours.  This  process 
can  be  accompKshed  in  half  the  time  by  employing  50 
grammes,  but  in  that  case  greater  care  and  accuracy  are 
required  in  working.  The  ash  is  transferred  to  a  platinum 
dish,  for  weighing,  by  the  help  of  the  feather  end  of  a 
quiU  pen,  with  which  the  interior  of  the  porcelain  dish 


INSPECTION    AND    EXAMINATION    OF    BREAD  515 

can  be  very  thoroughly  cleaned.  Before  the  weight  is 
taken,  it  is  desirable  to  complete  the  incineration  by  heat- 
ing the  contents  of  the  platinum  dish  to  redness  for  a 
short  time,  to  ensure  a  thorough  burning.  If  the  operator 
is  possessed  of  a  large  £5  platinum  dish,  the  employment 
of  the  Berlin  dish  is  dispensed  with.  The  ash  should  be 
weighed.  It  does  not  in  pure  bread  exceed  2  grammes 
in  1 0  0  grammes  of  bread,  or  2  per  cent. 
For  example : — 

Ash  and  platinum  dish     .  2 7 "7 70 

Platinum  dish      .  .  26-205 


Ash        .  1-565 

Result  1-5  per  cent  of  ash. 

Silica. — Add  5  c.  c.  to  10  c.  c.  of  strong  hydrochloric  silica  varies 
acid  (pure)  to  the  ash  in  the  platinum  dish.  Add  20  breTdfrom 
c.  c.  to  30  c.  c.  of  distilled  water,  and  boil,  taking  care  to  '•^^^  *°  '^^^ 

IT-  rrn         1  T'T-  11  1  P®""  cent. 

avoid  splashing.  The  hot  liquid  is  passed  through  a 
small  Swedish  filter  paper  into  a  beaker.  Place  some 
distilled  water  in  the  platinum  dish  and  heat  to  boiling 
point,  using  a  feather  or  glass  rod  to  detach  any  solid 
particles  adhering  to  the  sides  of  the  dish.  Pour  these 
washings  through  the  filter.  Finally  wash  the  precipitate 
on  the  filter  with  hot  distilled  water  by  the  help  of  a 
wash  bottle.  The  well-established  rule  of  avoiding  the 
addition  of  the  wash  water  to  the  filter  before  the  mother 
liquor  has  entirely  passed  through  it  should  of  course  be 
remembered. 

As  the  precipitate  on  the  filter  has,  like  many  other 
precipitates,  a  tendency  to  clamber  up  the  sides  of  the 
filter  and  pass  down  between  the  filter  and  the  funnel, 
it  is  necessary  to  wash  it  down  the  sides  of  the  filter  by 
the  help  of  a  jet  of  water  from  the  wash  bottle. 

A  great  bulk  of  liquid  is  to  be  avoided  in  making 


516  INSPECTION    AND    EXAMINATION    OF    BREAD 

these  washings.  Several  successive  washings  with  small 
quantities  of  hot  distilled  water  are  preferable  to  the 
j)ractice  of  using  two  or  three  large  quantities.  Let  the 
filter  drain  and  dry,  by  suspending  the  funnel  containing 
it  in  a  ring  of  a  retort  stand,  at  such  a  distance  above  a 
Bunsen's  burner,  or  a  spirit  lamp,  as  to  prevent  the 
possibility  of  ignition  or  charring.  The  filter  and  the 
precipitate  on  it  will  soon  dry.  Fold  the  filter  and 
carefully  transfer  it  into  a  little  platinum  or  porcelain 
crucible  provided  with  a  cover  (or  into  a  platinum  milk 
dish),  and  burn  the  filter  to  an  ash,  and  weigh. 

It  is  advisable  to  employ  round  Swedish  filter  papers 
yielding  definite  and  known  quantities  of  ash,  as,  for 
example,  one  or  two  milligramme  filter  papers.  If  none 
are  at  hand,  cut  a  filter  of  the  requisite  size  out  of  a 
sheet  of  filter  paper  and  weigh.  The  weight  of  the  ash 
is  always  -|-  per  cent  the  weight  of  the  filter  paper ; 
therefore,  a  filter  paper  weighing  500  milligrammes  has 
an  ash  of  2-|-  milligTammes.  We  have  now  arrived  at 
the  weight  of  the  silica  in  the  total  ash. 

Tor  example  : — 

Platinum  dish  and  asli  .  7-8200 

Disli  .  .  .  7-7700 


Weight  of  asli  .  .  -0500 

„     of  filter  asli  .  .  -0015 


•0485 
Eesult  -0485  per  cent  of  silica. 

Alumina.  Aluminct. — Unadulterated  flour,  with  which  bread  is 

made,  contains  such  a  variable  amount  of  alumina,  in  part 
due  to  clay  and  other  extraneous  matter,  that  it  seems  im- 
possible to  draw  a  line  between  bread  adulterated  or  not 
adulterated  with  alum.  The  differences  between  the  amount 
of  alumina  in  Calcutta,  Paissian,  and  English  grown  wheat 


INSPECTION    AND    EXAMINATION    OF    BREAD  517 

is  very  striking.  California  sends  us  wlieat  wliicli  yields 
a  remarkably  small  amount  of  alumina,  whilst  Egyptian 
wheat  exhibits  an  enormous  amount.  At  first  it  was 
stated  that  the  average  amount  of  alumina  present  in 
good  unalumed  bread  should  be  considered  as  equivalent 
to  2  grs.  in  the  4  lb.  loaf;  then  analysts  decided  that  10 
grs.  of  alum  in  the  4  lb.  loaf  should  be  substituted  as  a 
minimum  to  be  subtracted  from  the  result  of  an  analysis. 
The  investigations  of  Dr.  James  Bell  and  others  have 
since  shown  that  this  allowance  is  insufficient,  as  alumina 
in  the  form  of  silicate,  equivalent  to  more  than  40  grains 
of  alum  in  the  4  lbs.,  has  been  found  in  good  unadul- 
terated flours.  He  states  ^  that  no  rule  can  be  laid  down 
for  the  correction  which  should  be  made.  It  has  now 
become  the  established  rule  amongst  analysts,  that  a  bread 
or  flour  should  never  be  declared  adulterated  with  alum, 
although  it  may  yield  a  large  amount  of  alumina,  if  the 
logwood  and  carbonate  of  ammonia  test  fail  to  give  it  a 
permanent  blue  or  lavender  colour. 

So  the  whole  question  as  to  whether  a  bread  is  or  is 
not  alumed,  resolves  itself  very  much  into  a  consideration 
of  the  behaviour  of  the  bread  when  subjected  to  the  log- 
wood test.  A  Fellow  of  the  Chemical  Society  writes 
thus  :  ^ — "  Since  it  is  impossible  to  fix  upon  a  standard  of 
natural  alumina,  and  since  it  is  erroneous  to  regard  its 
amount,  even  in  the  presence  of  alum,  as  in  any  degree  a 
measure  of  alum,  it  may  be  asked  what  is  the  use  of 
estimating  it  at  all  ?  I  venture  to  suggest  that  it  might 
indicate  whether  the  grain  was  or  was  not  cleansed 
properly  before  grinding,  but  the  estimation  of  silica 
would  answer  just  as  well." 

The  Hadow-Horsley  reagent  for  the  detection  of  alum  ^iie  Had  w- 

Horsley's 
Test  for 

^  Analysis  and  Adulteration  of  Foods.  alum. 

^  "Alum  in  Flour  and  Bread,"  by  M.   D.  Penney,   Chemical  News, 
February  21,  1879. 


518  INSPECTION    AND    EXAMINATION    OF    BREAD 

in  bread  is  employed  as  a  qualitative  auxiliary  test  by 
analysts.      It  is  prepared  thus  : — • 

"  1.  Make  a  tincture  of  logwood  by  digesting  for  eight 
hours  5  grammes  of  freshly-cut  logwood  chips  in 
1 0  0  c.  c.  of  strong  alcohol,  and  filter ; 

"  2.  Make  a  10  or  15  per  cent  solution  of  carbonate  of 
ammonia  in  distilled  water, 

"  A  teaspoonful  of  each  solution  mixed  with  a  wine- 
glassful  of  water  in  a  white  ware  vessel  forms  a  pink- 
coloured  liquid.  Bread  containing  alum,  immersed  in 
this  liquid  for  five  minutes  or  so,  and  then  placed  upon 
a  plate  to  drain,  will  in  an  hour  or  two  become  blue  or 
lavender  on  drying ;  but  if  no  alum  is  present,  the  pink 
colour  fades  away  and  gives  place  to  a  dirty  brown. 
Salts  of  magnesia  yield  with  this  test  a  somewhat  bluish 
colour,  which  is  not  so  permanent  as  that  furnished  by 
alum.  Moreover,  the  increased  weight  of  ash  indicates 
mineral  additions.  If,  on  drying,  a  greenish  tinge  appears, 
an  indication  of  copper  is  afforded,  as  carbonate  of  am- 
monia produces  that  colour,  but  never  a  blue." 

Dr.  James  Bell,  of  Somerset  House,  writes  ^  of  this 
test,  "  It  is  one  which  we  have  never  known  to  fail  to 
indicate  alum."  Mr.  Wynter  Blyth  has  suggested  ^  an 
improvement  of  it  with  gelatine  in  this  wise :  "  From 
300  to  400  grs.  of  bread  are  crumbled  in  distilled  water 
and  a  slip  of  pure  gelatine  added,  and  the  whole  allowed 
to  soak  for  12  hours.  On  dissolving  the  gelatine  in  a 
little  logwood,  to  which  its  own  volume  of  a  10  per  cent 
solution  of  ammonium  carbonate  has  been  added,  if  the 
bread  is  pure  the  solution  wiU  be  reddish-pink,  if  the 
bread  is  alumed  the  solution  will  be  blue." 

An  approximative  estimate  of  the  amount  of  alum 
present  may  be  made  by  the  help  of  a  known  quantity 
of  a  standard  solution  of  alum  (1  gramme  to  the  litre), 

1  Op.  cit.  2  Qp_  cit. 


INSPECTION    AND    EXAMINATION    OF    BREAD  519 

which  should  be  added  to  the  same  amount  (300  to  400 
grs.)  of  a  sample  of  unalumed  bread.  The  relation 
between  the  amount  of  silica  and  that  of  alum  should 
be  considered  in  the  examination  of  a  bread,  for  it  may 
have  been  made  of  flour  containing  much  clay  and  mud, 
such  as  is  found  in  Egyptian  wheats.  A  large  amount 
of  alum  in  conjunction  with  a  small  quantity  of  silica 
indicates  that  the  excess  is  due  to  the  addition  of  alum. 

The  amount  of  alum  generally  added  to  bread  adul- 
terated with  this  substance  varies  between  20  and  30 
grains  in  a  4  lb.  loaf,  although  more  than  100  grains 
have  in  exceptional  cases  been  discovered  in  the  same 
quantity  of  bread. 

It  does  not  necessarily  follow  that,  because  bread  on 
analysis  proves  to  have  been  alumed,  the  baker  has 
mingled  it  with  his  flour  in  the  manufacture  of  his  bread. 
Some  millers  alum  the  flour  before  they  supply  it  to  their 
customers. 

Accordingly,  when  a  loaf  is  purchased  for  analysis,  a 
sample  of  flour  from  each  sack  found  on  the  premises 
should  also  be  taken  for  examination. 

In  rare  cases,  salt,  which  is,  of  course,  freely  used  in 
bread  making,  has  been  found  to  contain  alum. 


CHAPTER    L 

IXSPECTIOX    AXD    EXA:\nXATIOX    OF    MILK 

Milk  contains  the  three  classes  of  principles  in  association 
with  water  which  are  requii'ed  for  human  food — namely, 
the  Albuminous  or  Xitrogenous,  the  Oleaginous,  and  the 
Saccharine — and  is  the  only  article  supplied  by  nature 
which  combines  all  the  elements  requisite  to  secure 
healthy  nutrition  in  a  form  suited  to  the  young  animal. 
It  must  not  be  omitted,  therefore,  from  the  category  of 
the  necessaries  of  life  to  which  the  attention  of  the 
Medical  Officer  of  Health  is  restricted,  although,  if  he  does 
not  hold  the  post  of  public  analyst,  he  may  not  find  it 
requisite  to  make  an  official  examination  of  a  milk,  except 
as  a  guide  for  himself  in  his  own  investigations  as  to  the 
origin  and  spread  of  diseases.  On  professional  analysts 
rests  the  duty  of  ascertaining  the  amount  of  water  added, 
or  the  amount  of  fat  abstracted,  in  order  to  aid  the  law  in 
the  punishment  of  fraud.  Enteric  fever,  scarlet  fever, 
and  diphtheria,  are  diseases  which  have  been  indubitably 
spread  through  the  medium  of  milk.  The  exact  manner 
in  which  the  poisons  of  these  diseases  obtain  entrance  to 
this  liquid  food  often  taxes  the  skill  of  the  Medical  Officer 
of  Health.  In  milk  outbreaks  of  typhoid  fever  not  a 
single  link  in  the  chain  of  evidence  should  be  neglected. 
If  the  health  officer  finds  on  analysis  that  the  water  used 
in  the  dairy  contains  excremental  filth,  and  traces  the 
pollution  to  its  source,  which  has  been  infected  with  the 


INSPECTIOX    AND    EXAMINATION    OF    MILK  521 

specific  poison  of  the  disease,  it  is  still  desirable  to 
ascertain  whether  or  not  the  milk  has  been  diluted  with 
water.  Here  is  an  example  of  the  assistance  that  such 
an  examination  may  afford  a  Medical  Officer  of  Health  : — 
Fever  once  appeared  in  a  large  public  school,  and  as  no 
mode  of  the  entrance  of  the  poison  could  be  discovered,  it 
was  at  first  supposed  to  have  arisen  svA  sponte.  The 
water  supply  on  analysis  proved  to  be  pure.  The  milk 
was  supplied  from  two  or  three  sources,  and  was  not 
complained  of.  On  making  an  analysis  of  the  milk  it 
was  found  to  have  been  manipulated  with  water.  An 
analysis  of  the  w^ater  from  each  of  the  three  farms 
whence  the  milk  was  derived  was  made,  and  one  of 
these  waters  was  discovered  to  be  polluted  with  animal 
excrement,  whilst  the  other  two  waters  were  of  un- 
doubted purity.  On  visiting  the  dairy  farm  possessing 
the  polluted  water  supply,  it  transpired  that  the  closet 
and  well  were  in  affectionate  proximity,  and  that  the 
former  had  recently  received  the  specific  poison  of  the 
disease  from  one  of  the  labourers.  If  milk  under  such 
circumstances  should  not  evince  by  chemical  examination 
any  decided  departure  from  the  normal  state  of  the 
secretion,  due  regard  being  paid  to  its  variation  in  com- 
position, by  reason  of  the  age  and  food  of  cow,  time  after 
calving,  weather,  etc.,  it  must  not  be  concluded  that  the 
poison  of  the  disease  has  not  been  communicated  to  the 
milk  through  the  medium  of  water,  for  there  is  every 
reason  to  beheve  that  the  smallest  ciuantity  of  w^ater 
containing  the  specific  poison,  such  as  may  be  introduced 
by  merely  rinsing  the  milk-cans,  is  sufficient  to  infect  a 
large  quantity  of  milk.  An  analysis  of  milk  in  suspected 
tj'phoid  outbreaks  often  affords  only  negative  evidence. 
The  undoubted  admixture  of  water  with  milk  introduces 
us  to  a  fresh  scent  in  our  endeavours  to  trace  the  intro- 
duction of  the  poison,  although  the  absence  of  signs   of 


522 


INSPECTION   AND    EXAMINATION    OF    MILK 


any  decided  adulteration  does  not  preclude  the  possibility 
that  the  milk  may  have  been  poisoned  through  the 
medium  of  water.  As  a  rule,  however,  milks  fraudu- 
lently watered  are  adulterated  with  at  least  10  per  cent 
of  water.  ISTo  ray  of  light,  however  feeble,  should  be 
neglected  in  tracking  this  prevalent  and  wholly  prevent- 
able disease.  The  microscope  affords  also  aid  which  is 
not  to  be  despised.  In  milk  outbreaks  of  scarlet  fever  a 
comparison  should  be  made  with  this  instrument  between 
milk  that  has  been  exposed  to  infection — as,  for  example, 
from  being  stored  within  a  few  yards  of  persons  suffering 
or  recovering  from  this  disease — and  the  milk  of  the 
same  animals  that  has  not  been  thus  endangered,  with 
the  object  of  discovering  epithelial  scales,  for  its  poison 
would  seem  to  be  mainly  distributed  through  the  air  by 
the  aid  of  the  dust  of  the  skin  to  which  it  attaches  itself 
Good  milk,  the  chemical  composition  of  which  is  to 
be  found  in  every  physiological  work,  is  slightly  acid  or 
neutral,  or  very  feebly  alkaline  to  litmus  paper.  Its 
specific  gravity  is  about  1-030  or  1-034. 


j:p^^  §0^°' 


)'±o  „9 


''% 


,00 


w&x  Ooo  on     "  o  Op°V'-'oo     °» 
=  _orS  ffSV  o     £v,a«  l^^-bi,  „  1^   Hie 


g°n  O  ^^ — 


0  00 


o  o  nO    0 
OO      ^' 


b^°l%Sj°°o^.O^ 


.,  -oO°oSW 

'«,»°o  o   _,0  o  ^ 

Fia.  101. — Milk  containing  colostrum  corpuscles, 
at  a  and  elsewhere.    (After  Carpenter.) 


Microsco^pic  Appearance. 

Milk  is  seen  to  consist  of 
a  number  of  oil  globules 
of  different  sizes,  called 
milk  globules,  and  a 
little  epithelium  sus- 
pended in  a  somewhat 
turbid  fluid.  Immedi- 
ately after  calving  are 
sometimes  perceived 
large  yellow  compound 
bodies  termed  colos- 
trum corpuscles.  The 
secretion  of  the  colos- 


INSPECTION    AND    EXAMINATION    OF    MILK  523 

trum  immediately  after  birth  is,  as  every  one  knows, 
designed  to  purge  the  young  animal. 

In  the  milk  of  a  woman  suffering  from  an  acute 
disease,  colostrum  corpuscles  and  large  granular  cells 
rich  in  fat  are  visible.-^ 

Foreign  bodies  are  sometimes  noticed  by  the  micro- 
scope in  milk ;  for  example,  blood  and  pus  corpuscles, 
epithelium,  etc. ;  also  mineral  matters,  such  as  chalk, 
starch,  vegetable  organisms. 

Physical  Peculiarities. 

Milk  coagulating  during  or  immediately  after  milking, 'Freshunk 
especially  after  it  is  warmed. — The  secretion  of  this  acid  *^°^^^ 
milk  may  be  owing  (1)  to  inflammation  of  udder,  (2)  to 
digestive  disturbance  or  a  febrile  state. 

Yellow  Milk. — This  colour,  when  not  due  to  thcYeiiowMiik. 
colostrum  of  newly-calved  cows,  is  observed  when  there 
is  irritation  or  congestion  of  the  udder.  Dairymen  colour 
their  milk  with  annato.  When  milk  is  boiled  the 
colouring  matter  remains  in  the  whey.  An  unnatural 
yellow  colour  of  cream  is  sometimes  produced  by  an 
organism  called  by  Klein  the  Bacterium  xanthinum,  and 
by  Verheyen  the  Vibrio  xanthogenus.  The  eating  of 
orchids  and  of  Rheum  •palmatum  by  cows  has  been  said  to 
render  the  milk  of  a  yellow  colour. 

Viscid  Milk,  which  is  stringy  and  mucus-like  when  viscid  Miik. 
poured  from  one  vessel  to  another,  and  has  a  stale  un- 
pleasant taste,  has  been  found  to  contain  a  large  pro- 
portion of  albumen,  as  well  as  carbonate  of  ammonia. 
Microscopically  it  resembles  colostrum,  but  it  is  distin- 
guished from  it  by  its  power  of  producing  the  same 
alteration  in  a  large  quantity  of  healthy  milk.  The 
^dscidity  of  milk  has  been  ascribed  to  a  half-starved 
condition  of  cows,  and  to  damp  unwholesome  dairies 
^  Lehman's  Physiological  Chemistry. 


524  INSPECTION    AND    EXAMINATION    OF    MILK 

The  colours  of  Mue,  red,  and  green  milk  or  cream 
are  all  probably  due  to  the  development  of  organisms, 
respecting  the  nature  of  which  very  little  is  at  present 
known.  The  ferment  produced  will  give  rise  to  the 
same  alteration  when  a  small  portion  of  either  of  these 
milks  is  added  to  a  large  quantity  of  good  milk.  Several 
micro-organisms  are  believed  to  possess  the  power  of 
producing  the  lactic  fermentation,  whilst  the  Clostri- 
dium htityricum,  called  also  the  Bacillus  hutyricus,  is 
alone  capable  of  converting  lactic  acid  into  butyric 
acid. 
Blue  Milk.  Blue  Milk  has  a  disagreeable  taste,  and  has  been 
found  to  produce  diarrhoea  and  severe  febrile  gastritis.-^ 

Pigs,  rabbits,  and  sucking  calves  suffer  from  diarrhoea 
after  feeding  on  it. 

A  distinction  has  been  drawn  between  milk  wdiich 
is  blue  when  drawn,  and  that  which  is  blue  when 
coagulated  or  in  the  condition  of  cream,  the  former  being 
supposed  to  be  not  injurious  and  the  latter  injurious  to 
health.  The  probability  is  that  the  colour  is  due  to  one 
and  the  same  organism,  which  becomes  poisonous  only  at 
a  certain  stage  of  its  development.  It  has  been  described 
under  the  name  of  the  Bacillus  syncyanus. 

The  blue  colour  has  been  attributed  to  the  consump- 
tion   by   the    cows   of    certain    plants,   as    the    Myosotis 
jKdustris,    Mercuricdis    perennis,    Fago23yrum,    Polygonum 
avicidare,  and  Anchusa  tinctoria. 
Reddish  Cows  fed  ou  madder  or  galium  (commonly  called  bed- 

straw)  have  been  found  to  secrete  a  reddish  milk.^ 

Milk  is  a  fluid  which  is  extremely  liable  to  be  affected, 
as  to  its  odour  and  taste  and  quality,  by  the  food  of  the 
cows  that  secrete  it,  and  by  chemical  changes  that  are 
due  to  foul  conditions  of  air  to  which  it  may  be  exposed, 

1  Virchow's  Archiv.,  Band  xliii.  p.  161  (1868). 
-  Reimann's  Fdrber  Zcitung, 


Millc. 


INSPECTION    AND    EXAMINATION    OF    MILK  525 

and  to  the    special   ferments  ^  which   attach   themselves 
to  it. 

We  are  all  familiar  with  the  taste  of  turnips  in  onr  changes  in 
milk  and  butter  during  the  depth  of  winter.      Vine   and  odour, 
chestnut  leaves  will  render  milk  bitter,  and  beech  leaves 
will  diminish  the  supply  of  milk.      Milk  is  also  bitter  if 
bitter  medicines  have  been  administered  to  the   cow,  and 
in  disease  of  the  liver. 

Milk  has  been  found  to  possess  a  sweet  or  bitter  unpleas- 
ant taste  and  a  "rotten"  disagreeable  odour  when  supplied 
by  cows  badly  kept  on  damaged  forage  and  filthy  water, 
and  when  kept  in  dirty,  unwholesome,  damp  dairies.^ 

Mr.  Smee  exposed  milk  to  sewer  gas,  but  could  find 
no  change  in  composition  on  making  a  chemical  analysis. 
On  distilling  the  milk  at  a  temperature  not  exceeding 
120°  F.,  a  distillate  was  obtained  which  had  an  un- 
pleasant taste  and  an  offensive  smell.  "  Tasting  the 
distillate  set  up  intense  headache,  vigorous  rapid  pulse, 
and  was  followed  by  severe  diarrhoea.^  Milk  exposed 
to  the  vapour  arising  from  animal  matter  undergoing 
putrid  decomposition,  similarly  treated,  was  offensive  and 
produced  results  dangerous  to  health. 

Chemical  Examination. 

Milk  is  adulterated  with  many  substances,  some  (such 
as  salt)  to  cover  the  addition  of  water,  others  to  render  its 
estimation  difficult,  and  some  (such  as  borax  and  salicylic 
acid  in  minute  quantities)  to  increase  its  keeping  properties. 
The  chief  adulteration  of  milk  consists  in  the  addition  of 

^  Vide  p.  392  as  to  the  formation  of  a  poisonous  alkaloid  or  ptomaine 
named  tja'otoxicon  and  its  connection  with  infantile  diarrhoea. 

^  I  visited  a  dairyman's  establishment  once  where  the  water  in  the  cow- 
shed, with  which  the  milk  was  confessedly  adulterated,  was  sewage  water, 
and  the  cans  of  milk  were  stored  in  a  bedroom  redolent  of  organic  matter. 

^  Milk  in  Health  and  Disease. 


526  INSPECTION    AND    EXAMINATION    OF    MILK 

water,  which  has  been  carried  on  to  such  an  extent  in 
London,  that  it  has  been  found,  that  the  number  of  cows 
supplying  tlie  metropolis  with  milk  would  not  yield  more 
than  sufficient  to  provide  daily  each  inhabitant  with 
about  a  tablespoonful  of  pure  milk.  The  salt  may  be 
estimated  by  a  standard  solution  of  nitrate  of  silver  {vide 
page  136)  applied  to  a  solution  of  the  ash.  The  addition 
of  carbonate  of  soda  to  neutralize  sourness  in  stale  milk  is 
shown  by  the  milk  yielding  a  high  ash  which  effervesces 
on  the  addition  of  an  acid.  Chalk,  gypsum,^  and  other 
inorganic  substances,  are  easily  detected  by  an  estima- 
tion of  the  weight  of  the  ash.  It  is  desirable  that  the 
Medical  Officer  of  Health  should  be  able  not  only  to 
diagnose  these  milk  sophistications,  but  be  in  a  position  to 
ascertain  whether  a  milk  contains  the  normal  proportions 
of  its  principal  ingredients,  for  the  supply  of  a  young  child 
with  an  abnormally  poor  milk  {vide  page  533)  signifies 
the  deprivation  at  the  most  important  age  of  a  portion  of 
what  sometimes  is,  and  always  should  be,  its  sole  nourish- 
ment, which  may  lead  to  the  development  of  strumous  or 
some  other  disease  of  a  mal-assimilative  kind.  A  great 
change  has  been  of  late  effected  in  the  chemical  analysis 
of  milk,  which  has  principally  consisted  in  a  more  com- 
plete removal  of  the  fat,^  in  the  employment  of  the  specific 
gravity  test  corrected  for  temperature,  and  in  the  lowering 
of  the  minimum  limit  of  the  amount  of  "solids  not  fat"  below 
which  milk  is  to  be  considered  adulterated.     A  representa- 

■^  The  adulteration  of  milk  with  mineral  matters  appears  to  have  been  a 
very  ancient  custom,  if  the  statement  that  St.  Irenteus  wi'ote,  A.D.  140, 
"Lacte  gypsum  male  miscetur,"  is  to  be  credited. — Notes  and  Queries, 
5th  Series,  xi.  216. 

^  It  has  been  shown  that  at  least  '3  per  cent  more  fat  is  obtained  by  the 
plaster  process  than  by  the  Wanklyn  process,  and  another  '2  per  cent 
more  by  Adam's  coU  process  than  by  the  plaster,  so  that  at  least  "5  to  '6 
per  cent  more  fat  is  procured  by  the  Adam's  coU  than  by  the  "Wanklyn 
process. 


INSPECTIOIf   AND    EXAMINATION    OF    MILK  527 

tive  committee  of  the  analysts  of  tlie  country  have  for  the 
last  two  years  been  engaged  in  an  endeavour  to  improve 
our  methods  of  milk  analysis,  and  in  December  1885  for- 
warded their  Eeport  to  the  Council  of  the  Society  of  Analysts, 
which  report  contained  the  following  conclusions — 

"1.  As  to  the  Process  of  Analysis. 

"  That  in  future  the  method  to  be  recommended  for  adoption  by 
the  members  of  the  Society  of  Public  Analysts  be  as  under  : — 

"  (1)  Total  Solids. — These  to  be  estimated  by  evaporating  in  a 
platinum  dish  about  5  grammes  of  milk.  The  residue  to  be  dried 
to  practical  constancy,  at  the  temperature  of  a  water  oven  or  water 
bath. 

"  (2)  TJie  Process  of  Fat  Eo^radion,  with  Mr.  Adam's  paper  coils 
{vide  Estimation  of  Fat,  page  528). 

"  (3)  The  '  Bolids  not  Fat '  in  all  cases  to  be  determined  by 
difference.  "We  strongly  recommend  that  in  all  cases  the  specific 
graAdty  be  taken  as  a  useful  control. 

"  2.  As  to  Standards  or  Limits. 

"We  further  recommend  that,  concurrently  with  the  method 
above  laid  down,  the  following  be  the  limits  below  which  milk 
should  not  be  passed  as  genuine,  viz. — Total  solids,  11-5  per  cent, 
consisting  of  not  less  than  3  per  cent  of  fat,  thus  leaving  not  less 
than  8"5  per  cent  of  non-fatty  solids." 

Milk  should  always  be  analyzed  in  a  fresh  state,  for 
when  sour  or  otherwise  decomposed,  correct  determina- 
tions are  more  difficult.  To  ascertain  whether  or  not 
water  has  been  added  to  cows'  milk,  the  estimation  of  the 
amount  of  milk  solids  is  necessary. 

Determination  of  the   Total  Solids. — Procure  (1)  two  Average  of 
or  three  little  platinum  dishes  each  of  which  is  numbered  ;soikis"i2-s 
(2)  a  copper  water  bath  resembling  that  depicted  in  Fig.  per  cent. 
14,  provided  with  holes  corresponding  to  the  number  of 
little  dishes,  in  place  of  the  large  holes  there  exhibited ; 
and  (3)  a  bulb  pipette  gTaduated  to  5  c.  c.     Weigh  the 
dish  and  place  it  on  the  water  bath.      Having  shaken  the 
sample  of  milk,  place   5   c.  c.  of  it,  measured  with  the 


528  INSPECTION    AND    EXAMINATION    OF    MILK 

pipette  figured  below,  in  the  dish.  Light  the  Bunsen's 
burner,  and  boil  the  water  in  the  bath  \igorously. 
Complete  evaporation  to  dryness  will  consume  three  or 


Fig.  102.— Milk  Pipette. 

four  hours.  At  the  end  of  this  time  remove  the  platinum 
dish,  wi23e  it,  cool  it,  and  weigh  it  at  intervals  until  a 
constant  weight  is  obtained.  Some  place  it  in  a  hot  air 
oven  to  render  the  drying  complete.      For  example : — 

Milk  solids  and  platinum  dish  .  8"408 

Platinum  dish  (No.  2)  .  .  7-768 


Milk  Solids  -640 

Multiply  by  20  to  obtain  the  amount  present  in  100 
c.  c.  of  the  milk — 

•640  X  20  =  12-80  grammes  in  100  c.  c.  of  milk. 

As  100  c.  c.  of  average  milk  weigh  102-9  grammes, 
it  is  necessary,  if  it  is  wished  to  obtain  a  percentage 
statement  (which  is  more  easily  understood  by  the 
public),  to  divide  by  1-029. 

12-80  grammes  in  100  c.  c.  of  milk 4- by  1*029  =  12-44  per  cent 
of  milk  solids. 

The  milk  solids  of  other  animals  are  : — 


Per  cent. 

Analyst. 

Woman 

12-50 

Bell. 

Mare 

11-60 

5J 

Ewe 

24-78^ 

J5 

Goat 

14-40 

Payer 

Ass 

9-50 

55 

Average  of  Determination  of  the  Fat. — If  it  is  considered  desirable 

fat  ranges  ^^  l^now  the  cxteut  of  Watering  to  which  a  milk  has  been 

from  3-5  to  ° 

about  4  per  i  _^ijQ^^t  11  per  cent  of  this  large  amount  cousists  of  fat. 
cent. 


INSPECTION    AND    EXAMINATION    OF    MILK  529 

subjected,  it  is  necessary  to  estimate  the  amount  of  fat  in 
the  milk.  "  Pipette  5  c.  c.  of  milk  into  a  beaker  2 
inches  deep  by  1^  inch  in  diameter,  weigh  and  place  into 
it  one  of  Mr.  Adam's  coils,  viz.  a  rolled  up  strip  of  white 
demy  blotting-paper  (sharply  cut  to  2i  inches  wide,  and 
22  inches  long),  which  must  have  been  previously  ex- 
tracted with  ether  in  a  Soxhlet  apparatus  (to  removtj 
resinous  soap  employed  in  the  manufacture  of  such  paper) 
and  the  ether  driven  off.  When  as  much  as  possible  of 
the  milk  has  been  taken  up  by  the  paper  the  coil  is 
removed  and  placed  dry  end  downwards  upon  a  slip  of 
glass,  and  the  beaker  (which  should  be  kept  covered  by 
a  bell  jar  during  the  absorption  of  the  milk)  is  at  once 
re-weighed.  Dry  the  coil  in  a  water  oven  for  a  period 
of  one  to  two  hours,  and  extract  the  fat  by  ether  in  a 
"  Soxhlet "  apparatus,  twelve  syphonings  at  least  being 
necessary ;  the  flask  in  which  the  solution  is  collected 
being  as  small  and  light  as  possible.  Boil  off  the  ether 
and  place  the  flask  in  a  water  oven,  in  a  horizontal 
position,  and  dry  to  constancy,  allow  to  cool  for  about  10 
minutes  and  weigh."  Two  improvements  have  been 
suggested  on  the  official  method  by  Mr.  Wm.  Thompson.^ 
He  employs  filter  paper,  in  the  place  of  blotting-paper, 
which  does  not  need  extraction  with  ether  before  use, 
because  the  amount  of  extract  contained  therein  is  so 
small  ("0006  gramme)  as  to  fall  within  the  region  of 
experimental  error.  Whilst  fixing  one  end  of  the  strip 
of  filter  paper  (21  x  2  J  inches)  between  two  glass  rods, 
and  holding  the  other  extremity  in  the  left  hand,  5  c.  c. 
of  the  milk  are  diffused  over  the  paper  thus  horizontally 
held,  by  means  of  a  pipette  having  a  long  stem  under  the 
bulb.  The  strip  of  paper  thus  moistened  with  5  c.  c.  of 
milk  is  dried  by  moving  it  backwards  and  forwards  over 
the  flame  of  a  Bunsen's  burner  or  spirit  lamp.     The  dried 

1  Analyst,  April  1886. 
2  M 


530 


INSPECTION    AND    EXAMINATION    OF    MILK 


r'V-, 


strip  is  made  into  a  scroll  by  coiling  it  around  a  glass  rod, 

and  is  then  introduced  into  a 
Soxhlet's  fat  extractor  in  which 
it  requires  half  a  dozen  syphon- 
ings. 

The  small  size  Soxhlet's  Fat 
//  \/^  Extractor   will    be   found    most 

convenient,  and  enough  ether  is 
poured  into  it  to  nearly  reach 
the  upper  opening  into  it  of  the 
tube  through  which  the  ether 
vapour  ascends.  The  ether  boils 
at  a  very  low  temperature,  so 
the  gas  jet  or  spirit  lamp  flame 
should  be  very  small.  As  the 
ether  in  the  flask  boils,  the 
vapour  passes  up  through  the 
tube  into  the  extractor,  en 
route  to  the  condenser  where, 
being  condensed,  it  falls  back 
into  the  extractor,  until  the 
latter  is  filled  to  the  level  of  the 
top  of  the  syphon  which  then 
runs  the  ether  back  into  the 
flask,  carrying  with  it  in  solu- 
tion some  of  the  fat.  The  ex- 
tractor again  and  again  fills  and 
discharges  itself  so  long  as  the 
heat  is  maintained.  At  the  con- 
clusion of  the  extraction,  when 
the  extractor  is  nearly  full  of 
ether,  the  flame  and  condenser 
should    be    removed,    and     the 

ether  be  allowed  to  syphon  off  into  a  bottle  for  future  use. 

If  all  the  ether  in  the  flask  has  not  been  distilled  over, 


^ 


a  SoxMet  Fat  Extractor. 

6  Its  syphon. 

c  Glass  Liebig's  condenser  with 
openings  for  attachment  of 
indiaruhber  tubes,  through 
which  water  eaters  and  flows 
away. 

d  Flask. 

e  Shallow  beaker  containing  water. 

f  Bunsen's  burner. 

g  Coil. 

'i  h  Water. 


INSPECTION    AND    EXAMINATION    OF    MILK  531 

the  apparatus  should  be  fitted  together  again  and  the  re- 
maining portion  distilled  and  syphoned  off  into  the  bottle. 

The  weight  of  the  fat  derived  from  the  known  amount 
of  milk  operated  on  being  obtained,  the  percentage  can 
be  easily  calculated  in  the  manner  previously  explained. 

Determination    of   the    solids    not  fat.  —  Deduct    the  Average  of 
quantity  of  fat  from  the  total  milk  solids,  and  the  import-  fat,"  9  per 
ant  datum  "  solids  not  fat "  is  obtained.      Dr.  James  Bell  '^'^^*- 
states  that  in  the  case  of  individual  cows  they  vary  from  8-00 
to  11  "2  7  and  in  the  case  of  dairy  samples  from  8 "50  to 
9-91,  but  that  the  average  ranges  from  9 "0  to  9*1  per  cent. 

Determination  of  ash. — The  adulteration  of  milk  with  Average  of 
chalk  or  other  inorganic  substance  is  easily  detected  by  an  cent, 
estimation  of  the  ash.      This  determination  also  serves  to 
confirm  or  otherwise  the  examination  as  to  total  solids,  for 
a  milk  highly  adulterated  with  water  gives  too  low  an  ash. 

Place  the  platinum  dish  containing  the  dried  milk 

solids  on  a  pipe  triangle,  and  incinerate  by  means  of  an 

argand  burner  at  as  low  a  temperature  as  possible  (so  as 

to  avoid  the  volatilization  of  the  chlorides)  until  a  ivhite  ash 

is  obtained.      Allow  the  dish  to  cool,  and  weigh.     Subtract 

the  weight  of  the  dish  from  that  of  the  dish  and  ash,  and 

multiply  the  result  by  20  to  obtain  the  amount  of  ash  in 

100  c.  c.  of  milk.      For  example  : — 

Ash  and  platinum  dish.  .  .  .      7 '807 

Platinum  dish  (No.  2)  .  .  .7-768 


•039 
•039  X  20  =  -78  grammes  of  ash  in  100  c.  c.  of  milk. 

If  a  percentage  statement  is  required  divide  by  1*0 2 9. 

•78  4- 1-029  =  ^75  per  cent  of  ash. 

Determination  of  specific  qravity. — Dr.  Vieth  states  ^  '^'^^ 

^•n  •         o  -lno/^  Lactometer. 

that  the  specific  gravity  of  milk  varies  from    1-030  to 

1"034  with   very  few  exceptions,  or,  using  another   ex- 

^  Analyst,  April  1885. 


532  INSPECTION   AND    EXAMINATION    OF    MILK 

pression,  from  30  to  34  degrees,  and  that  the  specific 
gravity  of  a  mixed  milk,  i.e.  the  product  of  a  number  of 
cows,  should  never  fall  below  1'029  unless  an  excess  of 
cream  be  jDresent,  or  water  has  been  added.  The  more 
milk  sugar,  casein,  and  other  mineral  matter  contained 
in  milk,  the  greater  the  specific  gravity.  The  effect  of 
these  solids  is  more  or  less  counteracted  by  the  fat 
globules,  which  tend  to  lower  the  gravity  because  fat  is 
lighter  than  water.  As  the  addition  of  fat  tends  to 
diminish,  its  abstraction  (skimming)  increases  the  specific 
gravity,  bringing  it  up  sometimes  to  1"037.  The  practice 
in  the  milk  trade  is  to  rob  the  fresh  milk  of  cream  by 
pouring  into  it  skimmed  milk.  The  specific  gravity 
having  been  thus  raised  abnormally  high,  is  toned  down 
to  the  specific  gravity  of  good  rich  milk  by  dosing  it  with 
water.  Subject  to  a  correction  for  temperature,  the 
Society  of  Analysts  have,  notwithstanding,  decided  that 
the  readings  of  the  lactometer  may  be  usefully  employed 
to  check  results.  As  lactometers  are  generally  adjusted 
at  60°  F.,  the  corrected  specific  gravity  is  arrived  at  by  the 
subtraction  of  about  1  degree  from  those  furnished  by  the 
lactometer  for  each  10  degrees  of  temperature  heloiv  60°  F. 
and  by  adding  about  1  degree  for  each  10  degrees  ccbove 
60°  F.  For  intermediate  temperatures  the  proportionate 
fraction  of  1  degree  would  be  either  subtracted  or  added 
as  the  case  may  be,  e.g.  if  the  reading  of  the  lactometer 
was  25  degrees  at  the  temperature  of  56°  F.  the  corrected 
specific  gravity  would  be  about  24'6,  and  at  62°  F.  it 
would  be  about  25*2. 

A  great  controversy  has  for  some  time  been  carried  on, 
as  to  the  extent  to  which  the  components  of  milk  may 
be  influenced  by  breed,  feeding  and  keeping  of  cows,  age, 
time  of  year,  intervals  between  milking  times,  distance  of 
time  from  calving,  etc.  Milk  from  cows  of  the  Ayrshire 
breed  resembles  most  closely  human  milk.      Dr.  Sharpies 


INSrECTION    AND    EXAMINATION    OF    MILK  533 

points  out/  that  any  admixture  of  sugar  and  water  witli  tlie 
milk  of  a  cow  of  this  breed  to  make  it  resemble  human 
milk  will  certainly  do  more  harm  than  good.  It  is  free  also 
from  the  excess  of  fat  which  often  renders  the  milk  of  an 
Alderney  cow  unfit  for  the  food  of  delicate  children.  Certain 
cows  produce  what  are  termed  abnormal  milks ;  that  is,  Abnormal 
milks  that  are  exceptionally  rich  or  exceptionally  poor. 

The  following  analyses  of  rich  and  poor  milk  were 
made  by  Dr.  Shea  and  Dr.  J.  Bell  respectively.  The  rich 
milk  was  obtained  from  an  animal  fed  on  a  sewage  farm, 
chiefly  on  rye  grass : 


Sp.  Gr. 

Total  Solids. 

Fat. 

Solids  not  Fat. 

Ash. 

Rich  milk 

1-035 

14-8 

5-62 

9-20 

•85 

Poor  milks 

1-027 

10-4 

2-422 

8-0 

•69 

1-030 

10'9 

2-202 

8-6 

•62 

Milk  taken  at  the  commencement  of  a  milking,  which 
is  called  "  fore  milk,"  is  poorer  than  that  drawn  afterwards, 
and  that  which  is  obtained  at  the  termination  of  a 
milking  is  generally  rich  with  cream. 

The  law  provides  that  milk  shall  be  taken  to  mean 
whole  milk,  that  is,  the  mixed  milk  of  an  entire  milking 
of  a  number  of  cows. 

Although  the  milk  of  individual  cows  may  be  found 
to  vary,  the  milk  of  a  dairy  which  consists  of  a  mixture 
of  the  poor  with  the  rich  is  pretty  constant  in  composition. 
Its  range  in  composition  is  thus  given  by  Dr.  James  Bell.^ 

Percentage. 
Total  Solids.  Fat.  Solids  not  Fat.  Ash. 

12-8  to  13-2  3-8  to  4-1  9-0  to  9-1  'Vl  to  •?£ 

The  average  composition  of  11,389  samples  of  milk 
analyzed  in  1885  by  Dr.  Vieth  was  as  follows : — 

Total  Solids.  Fat.  Solids  not  Fat.  Sp.  Gr. 

13-06  3-93  9-13  1-032 

^  Proc.  of  American  Academy  of  Arts  and  Sciences,  vol.  xii.  1877. 
^  Too  low  in  consequence  of  the  imperfection  of  the  method  emploj-eJ 
for  its  extraction,  *  O}).  cit. 


534  INSPECTION    AND    EXAMINATION    OF    MILK 

It  lias  recently  been  stated/  that  the  introduction  of 
cream  separators  has  been  attended  by  the  development 
of  a  new  fraud,  which  consists  in  mixing  the  skim  milk 
derived  therefrom  with  ordinary  milk.  It  would  be 
doubtless  difiicult  to  distinguish  this  sophisticated  milk 
from  one  of  the  poor  abnormal  milks  from  healthy 
cows. 

The  Lancet  suggests  that  the  limits  of  strength  of  milk 
like  that  of  spirits  should  be  defined  by  Act  of  Parliament, 
and  that  no  milk  should  be  allowed  to  be  sold  with  less 
than  3  per  cent  of  fat  and  9  per  cent  of  solids  not  fat. 
An  Act  of  this  kind  would  give  milk  dealers  a  legal  right 
to  water  their  rich  milk  down  to  this  level.  They  would 
most  certainly  embrace  this  opportunity  of  making  a 
profit,  if  they  had  no  customers  for  their  richer  (higher 
priced)  milk.  In  the  interests  of  the  public  health,  it 
should  remain  a  punishable  offence  to  mix  any  water,  be 
it  much  or  little,  with  milk,  for  the  milk  epidemics  of 
enteric  fever  show,  that  the  admixture  of  the  smallest 
quantity  of  specifically  contaminated  water  with  milk  is 
sufficient  to  infect  large  numbers  of  milk  drinkers. 
standard  of  Great  differences  of  opinion  have  been  expressed  by 
good  milk.  a^j;ja^iygts  g^g  ^Q  whetlicr  a  milk  is  or  is  not  watered,  as  to 
the  quantity  of  water  employed  in  its  dilution,  and  as  to 
the  amount  of  cream  abstracted,  which  have  led  magistrates 
to  refuse  to  convict  in  cases  where  the  adulteration  is  not 
greater  than  10  per  cent  of  water,  so  that  milk  sellers 
may  cheat  to  at  least  this  extent  without  fear  of  punish- 
ment. The  want  of  agreement  between  analysts  has 
arisen,  partly,  from  the  imperfection  of  the  process  em- 
ployed, and,  partly,  to  the  abnormality  in  the  composition 
of  certain  unadulterated  milks.  It  is  to  be  hoped  that 
with  improved  methods  of  analysis  and  an  adjustment  of 
the  minimum  standard  which  have  now  been  established, 
1  Lancet,  March  6,  1886. 


INSPECTION    AND    EXAMINATION    OF    MILK  535 

the  milk  trade  may  be  carried  on  "with,  more  honesty  to 
the  consumer  and  more  justice  to  the  vendor. 

Milk  supplied  hy,  and  tainted  hy,  Diseased  Animals. 

Happily  this  secretion  diminishes  or  disappears  in 
many  of  the  diseases  of  animals,  notably  in  anthrax. 

Loiset  states  that  at  the  public  ahattoir  of  Lille  the 
employes  of  the  cattle  dealers  and  salesmen  have  con- 
sumed the  milk  of  diseased  cows  for  a  great  number  of 
years  without  the  slightest  inconvenience. 

Milk  is  not  the  diet  of  men  and  women,  but  of  child- 
ren, amongst  whom  the  mortality  under  five  years  of 
age  of  affections  resulting  from  improper  food  is  frightful. 
The  assertion  of  Loiset  as  to  the  harmlessness  of  the  milk 
of  diseased  animals  when  taken  by  men  seems  in  no  way 
to  determine  whether  or  not  such  milk  is  wholesome  as 
the  food  for  the  sucking  animal,  for  which  it  was  alone 
designed  by  nature. 

The  milk  of  diseased  animals  does  not  keep  well.  It 
is  found,  on  microscopic  examination,  to  contain  pus, 
blood,  and  a  larger  quantity  of  epithelium  than  is  present 
in  good  milk,  casts  of  lacteal  tubes,  vibriones,  cells, 
granules,  etc.  The  milk  of  animals  that  have  been  driven 
fast,  which  is  termed  "  heated  milk,"  has  been  found  to 
produce  colic  and  diarrhoea  amongst  children. 

Cattle  Plague. — There  is  no  evidence  to  prove  that  the  cattie 
milk  of  animals  suffering  from  cattle  plague  is  hurtful.  ^1^""®°^, 

o  Jr     &  Rinderpest. 

The  changes  that  occur  in  it  are,  according  to  Dr.  A. 
Gamgee,  as  follows  : — 

1.  Eemarkable  diminution  of  sugar  of  milk. 

2.  Enormous  increase  (except,  perhaps,  at  the  com- 
mencement) of  butter. 

3.  Slight  increase  of  salts, 

4.  The  casein  is  generally  increased. 

The  milk  of  animals  in  a  state  of  disease  which  exhibits 


536 


INSPECTIOX    AND    EXAMINATION    OF   MILK 


Pleuro- 
pneumonia. 


Foot-and- 

Mouth 

Disease. 


such  a  derangement  in  the  normal  proportion  of  its  ingredients 
cannot  be  wholesome  as  the  food  for  infants  and  children. 

Contagious  Pleuro-2oneu7nonia. — There  is  no  evidence 
to  prove  that  the  milk  of  animals  affected  with  this  dis- 
ease is  hurtful  to  adults  or  middle-aged  persons. 

Foot-and-mouth  Disease. — Much  discussion  has  taken 
place  as  to  whether  the  milk  of  cows  suffering  from  this 
disease  is  injurious  or  not  to  man. 

Pigs  fed  with  the  milk  of  animals  thus  affected  are 
invariably  seized  with  the  disease  in  a  few  hours.  It 
generally  destroys  sucking  pigs  and  calves. 

Aphthous  and  herpetic  patches,  followed  by  sores,  and 
sometimes  diarrhoea,  have  been  attributed  to  the  use  of 
such  milk. 

These  symptoms  have  naturally  been  observed  most 
amongst  children,  because  they  are  our  great  milk-com- 
sumers.  The  condition  of  the  milk  differs  much,  accord- 
ing as  the  udders  are  more  or  less  affected.  The  milk  is 
sometimes  unaltered  to  the  unaided  eye ;  at  others  it  is 
red,  or  brown,  or  yellow,  from  the  presence  of  blood  and 

Milk  in  Foot-and-Mouth  Disease.  Early  Stage.  P^^'  "^^  ^'Opy,  Or  resembl- 
ing whey  and  curds,  or 
foetid.  Microscopically  it 
is  found  to  resemble  the 
milk  of  cattle  affected 
with  rinderpest.  In  the 
first  stage  an  aggregation 
of  the  milk  corpuscles 
takes  place.  Subsequently 
pale,  fine  granules,  spheri- 
cal granular  cells  a  little 
larger  than  pus  corpuscles, 

bacteria,  vibriones,  epithelial  cells,  yellow  granular  masses 

not  unlike  colostrum  globules  seen  in  the  milk  of  cows 

newly  calved,  may  be  discerned. 


Fig.  104. — Clustering  of  Milk  Corpuscles, 
X  200  diam. 


INSPECTION    AND    EXAMINATION    OF   MILK 


537 


Foot-and-moutli  Disease.    Later  Stage. ' 


The  milk  from  which  the  drawing,  Fig.  105,  was 
made,  was  taken  from  a  cow  which  had  been  suffering 
from  the  disease  for  ten  days.  The  fluid,  after  standing  for 
some  time,  separated  into 
two  parts — a  curdy  de- 
posit and  an  amber-col- 
oured whey.  The  same 
elements  were  found  in 
both  constituents,  viz. 
large  granular  masses  of 
a  brownish-yellow  colour, 
numerous  pus-like  bodies, 
bacteria,  vibriones,  mov- 
ing spherical  bodies,  and 
a  few  milk  globules. 
These  morbid  elements 
were  found  in  specimens 
of  milk  which,  in  their 
physical  characters,  pre- 
sented    no     appreciable 

peculiarity     to      the      Un-  Fig.   105.— l.    Large  granular  bodies;  2.   Milk 
•IT   a\ral  corpuscles;  3.  Pus-like  bodies,     x  1300  diam. 

As  to  the  chemical  composition  of  the  milk,  he  has 
found  that  its  constituents  vary  much  in  amount  during 
the  progress  of  the  disease.  During  these  fluctuations 
there  is  a  deficiency  of  fat,  of  salts,  and  of  milk  solids  not 
fat,  the  last  named  falling  below  nine  per  cent  on  one  or 
two  occasions.^ 

Dr.  Klein  considers  ^  that  the  virus  of  foot-and-mouth 
disease  is  a  particular  kind  of  micrococcus,  and  he  has 
found  that  by  feeding  sheep  with  it — with  a  tw^entieth 
generation — the  typical  disease  is  reproduced. 

1  Lancet,  October  23,  1869. 

2  Froc.  of  the  Society  of  Public  Analysts,  1876,  vol.  i.  p.  233. 

^  Lancet,  January  2,  18 86. 


538  INSPECTION    AND    EXAMINATION    OF    MILK 

Continental  veterinarians  recognize  foot-and-mouth  dis- 
ease milk  by  its  easy  coagulability  on  tlie  application  of  the 
least  heat,  with  a  separation  into  numerous  little  curds 
.■^oating  on  the  whey,  the  latter  being  of  a  pale-bluish 
colour. 

There  is  a  strong  unpression  afloat  that  milk  drunk  in 
a  warm  state,  direct  from  a  cow  affected  with  the  disease, 
is  more  likely  to  produce  the  foot-and-mouth  disease  than 
when  cold,  and  that  by  boiling  the  milk  all  danger  is  re- 
moved. Dr.  Balfour  and  Mr.  H,  Watson  have  shown  that 
foot-and-mouth  disease  is  communicable  to  the  human 
subject  by  the  milk  obtained  from  cows  infected  with  this 
highly  contagious  acute  specific  fever.  There  appears  to 
be  no  doubt  but  that  the  discharges  from  the  vesicles  and 
sores  of  cattle  suffering  from  this  exanthem  will,  if  intro- 
duced  into  chaps  or  abrasions  of  the  skin  in  man,  create 
a  diseased  condition  resembling  the  foot-and-mouth  disease 
of  cattle,  attended  by  violent  constitutional  disturbance. 

Negative  e^ddence  as  to  the  injurious  nature  of  foot- 
and-mouth  disease  milk  is  afforded  by  the  investigations 
of  the  French  Commune  in  1839,  by  the  epidemics  of 
1810,  1811,  1834,  and  1835,  in  Paris  by  Lawson  Tait,^ 
and  Dr.  Thorne  Thome. 

Positive  evidence  is  given  by  EoU,  M'Bride,^  Gooding,^ 
Hislop,*  Latham,^  Briscoe,^  Nauheimer  and  the  Author. 
Cases  where  the  foot  was  also  involved  have  been  recorded 
by  Spinola''  and  Amyot.*^ 

There  are  grounds  for  thinking  that  aphthous  fever 

^  JTedical  Times  and  Gazette,  October  1869. 
^  British  Medical  Journal,  November  13,  1869. 
^  Medical  Times  and  Gazette,  Januar}^  1872. 
^  Edinburgh  Medical  Journal,  November  1869. 
*  British  Medical  Journal,  May  1872. 
^  British  Medical  Journal,  October  1872. 
''  Recueil  de  Med.   Vetir.,  1873,  p.  577. 
^  3Iedical  Times  and  Gazette,  November  4,  1871. 


INSPECTION    AND    EXAMINATION    OF    MILK  539 

assumes,  like  certain  eruptive  fevers  in  tlie  liuman  suljject, 
variations  in  type,  sometimes  being  very  mild  in  form  and 
at  others  of  a  malignant  kind.  It  is  very  certain  that 
the  milk  of  cows  suffering  from  this  disease  is  often 
consumed  without  ill  effects.  At  times  some  startling 
epidemic  occurs  in  connection  with  the  milk  supply  of 
cows  suffering  from  foot-and-mouth  disease,  as  for  example 
at  Dover  in  February  1884,  when  188  individuals  were 
affected  with  inflammatory  sore  throat,  enlargement  of  the 
lymphatic  glands  and  vesicular  eruptions  in  the  mouth, 
with  fatal  results  in  several  cases. -^ 

Stomatitis,  with  aphthous  ulcerations  in  the  mouth  of 
children,  is  known  to  be  produced  by  milk  which  contains 
pus  from  an  abscess  in  the  udder.  "  Sore  mouths  "  were 
exceedingly  prevalent  amongst  the  children  throughout 
the  country  during  the  extensive  outbreak  of  foot-and- 
mouth  disease  in  1869.  The  conclusions  arrived  at  by 
Dr.  Thorne  from  an  investigation  made  by  him  on  the 
"  Effects  produced  on  the  human  subject  by  consumption 
of  milk  fi'om  cows  having  foot-and-mouth  disease  "  are  as 
follows  :^—  (1)  That  a  disease  appears  sometimes  to  have 
been  produced  in  the  human  subject,  when  the  milk  of 
cows  suffering  from  foot-and-mouth  disease  has  been 
freely  used  without  being  boiled.  There  is  no  evidence 
to  show  whether  this  affection  is  of  a  specific  nature  or 
not ;  but  it  seems  to  consist  in  a  derangement  of  the 
alimentary  canal,  accompanied  by  febrile  disturbance,  the 
presence  of  vesicles  on  the  mucous  membrane  of  the 
mouth  and  tongue,  which,  having  ruptured,  leave  super- 
ficial ulcerations,  and  at  times  a  herpetic  eruption  about 
the  exterior  of  the  lips.  (2)  That  in  a  very  large  number 
of  cases  the  milk  of  cows  undoubtedly  affected  has  been 

^   "  Outbreak  of  Epidemic  Sore  Throat  following  use  of  milk  from  cows 
suffering  from  Aphthous  Fever,  "  bj'  Dr.  M.  K.  Robinson. 
2   Twelfth  Report  of  Medical  Officer  of  Privj'  Council,  1869. 


540 


IXSPECTIOX    AND    EXAMIXATIOX    OF    MILK 


Anthracic 
Diseases. 


Tubercu- 
losis. 


used  witliout  producing  any  noticeable  morbid  effects. 
This  absence  of  result  may,  though  only  to  an  inconsider- 
able extent,  have  been  due  to  the  smallness  of  the  con- 
sumption and  the  boiling  of  the  milk. 

Outbreaks  of  illness  from  the  employment  of  milk 
from  foot-and-mouth  disease  cattle  are  recorded  in  British 
Medical  Journal,  November  30  and  December  25,  1875, 
and  in  other  periodicals. 

The  knowledge  that  we  at  present  possess  as  to  the 
milk  in  this  disease  warrants  us  in  prohibiting  tlie  em- 
ployment of  it  in  any  shape  for  children,  and  in  dissuad- 
ing adults  from  using  it  even  when  boiled,  for  it  lacks  the 
physical  and  chemical  characters  of  good  milk. 

Anthracic  Diseases. — The  milk  of  animals  affected  with 
these  diseases  is  seldom  consumed,  partly  because  the 
secretion  is  very  soon  suspended,  and  partly  because  the 
physical  appearance  of  the  little  milk  that  is  supplied  pre- 
vents its  employment.  It  is,  so  Fleming  says,-^  of  a  dirty 
bluish  colour,  streaked  with  blood,  and  soon  becomes  putrid. 

Cases  are  recorded  of  diarrhoea  and  anthracic  affections 
having  been  produced  in  man  by  drinking  the  milk  of 
diseased  animals. 

Tuberculosis  amongst  Dairy  Cattle. — The  most  recent 
investigations  show  that  the  disease  known  as  tuberculosis 
in  man,  or  an  infective^  variety  of  it,  consisting  as  it  does 
of  the  deposition  of  tubercles  in  various  parts  of  the  body, 
especially  in  the  lungs  and  mesenteric  glands,  is  a  com- 
municable disease.  That  the  same  disease,  as  it  exists  in 
cattle,  can  be  conveyed  to  calves,  rabbits,  guinea  pigs,  etc., 
by  the  milk  of  an  animal  suffering  from  the  disease,  has 
been  proved  over  and  over  again  by  Chauveau,  Klebs, 
Gerlach,  Leisering,  Zlirn,  Bollinger,  and  others. 


^  A  Manual  of  Veterinary  Sanitary  Science  and  Police,  vol.  ii.  p.  200. 
^   Vide  paper  "On  an  infective  variety'  of  Tuberculosis  in  Man,  identical 
■with  Bovine  Tuberculosis"  by  Dr.  Creigliton  in  Lancet,  June  19,  1880. 


INSPECTION    AND   EXAMINATION    OF    MILK  541 

Klebs  asserts  that,  when  milk  has  been  deprived  of  its 
solid  particles,  the  tuberculous  virus  is  found  iu  the  fluid 
portion,  that  it  is  not  destroyed  by  cooking,  and  that  it  is 
all  the  more  active  as  the  disease  has  reached  to  an  ad- 
vanced stage.  He  is  of  opinion  that  tlie  disease  may  be  de- 
veloped in  children  through  the  medium  of  the  milk.  Such 
milk  is  liable  to  excite  diarrhoea  and  debility  in  children. 

Tuberculosis  is  a  disease  which  is  somewhat  common 
amongst  dairy  cows  that  are  shut  up  in  towns  in  close, 
ill-ventilated,  and  foul  cowhouses..  The  milk  of  such 
diseased  anmials  is  deficient  in  fat,  sugar,  and  nitrogenous 
elements,  whilst  it  possesses  an  increased  proportion  of 
earthy  matters.  In  these  days  when  the  filthy  feeding 
bottle,  containing  its  miitation  of  mother's  milk,  in  the 
shape  of  cow's  milk,  sugar,  and  water  and  a  pinch  of  salt, 
is  almost  uni^'ersally  substituted  for  the  supply  afforded 
by  nature,  can  it  be  wondered  at  that  there  should  be 
such  an  annual  Herodian  slaughter  of  innocents  from 
diarrhoea,  debility,  atrophy,  etc.,  when  it  is  remembered 
that  an  immense  quantity  of  the  milk  that  supplies  the 
bottle  is  derived  from  animals  thus  diseased  ? 

The  milk  of  milch  cows  suffering  from  tuberculosis 
should  not  be  employed  by  children.  The  milk  of  all 
institutions  occupied  by  the  young,  which  are  situated  in 
his  district,  should  be  analyzed  by  the  Medical  Officer  of 
Health,  for  he  should  be  acquainted  with  the  condition  of 
this  "  all  in  one  "  sort  of  nutriment,  as  supplied  in  large 
quantity  for  the  food  of  children. 

If  such  milk  should  contaui  a  deficiency  of  nitrogenous, 
fatty,  and  saccharine  matters,  as  exhibited  by  very  low 
milk  solids,  and  if  it  is  at  the  same  time  rich  in  mineral 
constituents,  there  is  a  suspicion,  if  unadulterated,  that  the 
milk  is  derived  from  animals  suffering  from  tuberculosis. 

The  examination  of  sputa  for  the  bacillus  of  tubercle 
(vide  fig.  23)  is  now  so  constantly  practised  by  the  medical 


542  INSPECTION    AND    EXAMINATION    OF    MILK 

man  as  to  render  its  recognition  in  other  secretions  an 
easy  matter.  It  is  reported  that  the  cows  of  Paris  have 
been  recently  found  producing  milk  which  contains  this 
bacillus,  and  that  the  Council  of  Health  have  advised  the 
closure  of  all  the  cowsheds  of  the  city.  Drs.  Bang  and 
V.  Storch  have  found  ^  that  the  cream  prepared  from  such 
milk  by  a  centrifugal  cream-producing  apparatus  contains 
tubercle  bacilli,  and  that  both  it  and  the  butter  made 
from  it  produce  tuberculosis  by  inoculation. 
Parturition  PartuHtion  OT  MUk  Fever. — A  sample  of  the  milk  of 
^g^,g|/  a  cow  thus  affected  was  found  by  Mr.  Smee^  to  contain 
an  abnormally  large  proportion  of  phosphates.  He  states 
that  during  the  progress  of  this  disease  the  earthy  phos- 
phates leave  the  animal's  bones,  producing  a  species  of 
moUities  ossium,  which  renders  them  exceedingly  liable 
to  fracture  after  recovery. 

In  this  disease  there  is  happily,  as  a  rule,  a  suppres- 
sion of  the  lacteal  secretion,  otherwise  we  should  have 
frequent  instances  of  the  injurious  effects  of  milk  of  such 
altered  composition  on  children. 

Changes  take  place  in  the  proportion  of  the  constitu- 
ents of  good  milk  in  other  diseases  of  cattle.  The  com- 
plaint known  as  the  "  grease  "  in  cows  is  attended  by  a 
decrease  of  the  alkaline  salts,  of  the  casein  and  the  fat 
(Herheyer).  In  the  vaccinia  of  cows  the  milk  is  strongly 
alkaline,  and  sugar  is  almost  absent  (Brewer). 
Garget.  Gctrget  is  a  name  under  which  is  included  more  than 

one  affection  of  the  udder  of  milch  cows,  which  is  attended 
by  the  secretion  of  milk  having  a  viscid,  ropy  or  stringy 
appearance  containing  pus  and  blood. 

The  outbreak  of  diphtheria  in  North  London  in  1878 

was  supposed  by  Mr.  W.  H.  Power,  one  of  the  Medical 

Inspectors  of  the  Local  Government  Board,  to  be  connected 

with  the  employment  of  milk  contaminated  with  the  secre- 

^  Lancet,  July  24,  1886.  2  Qj^^  ^it_ 


INSPECTION    AND    EXAMINATION    OF    MILK  543 

tions  of  animals  thus  affected,  but  the  chain  of  evidence  was 
incomplete.  Such  milk  is,  of  course,  quite  unfit  for  use, 
although  it  is  probable  that  the  milk  of  cows  affected  with 
the  milder  forms  of  the  complaint  is  consumed  without  ill 
effects.  Dr.  Thursfield,  in  a  case  of  garget  where  a  large 
quantity  of  milk  was  confiscated,  in  consequence  of  the 
presence  of  pus  and  blood  in  it,  employed  the  Guiacum 
test  of  the  late  Dr.  Day  of  Geelong,  as  confirmatory  of 
the  existence  of  blood  in  the  milk.  The  addition  of  a 
few  drops  of  the  tinct.  guaiaci,  followed  by  a  little  of  the 
solution  of  peroxide  of  hydrogen,  form,  when  used  in  con- 
junction, but  not  apart,  a  persistent  blue  tint,  diagnostic 
of  the  presence  of  blood. 

A  complaint  amongst  children,  known  as  milk-sickness, 
has  prevailed  in  America,  caused  by  the  unboiled  milk  of 
cows  that  have  fed  on  the  Rhus  toxicodendron,  which  pro- 
duces in.  these  animals  a  complaint  termed  "  the  trembles." 
The  milk  of  goats  that  have  fed  on  the  (Etliusa  cynaijium} 
and  on  euphorbiaceous  ^  plants,  has  been  found  to  be 
poisonous. 

Milk  is  apt  to  be  tainted  with  the  excretions  and  Miik  tainted 
secretions  of  man  and  other  animals  in  a  state  of  disease,  animals. 
The  excretions  from  the  intestinal  canal  in  enteric  fever, 
the  dispersed  dust  of  the  skin  after  scarlet  fever,^  the 
secretions  of  the  throat  in  diphtheria,  the  discharges  from 
cattle  suffering  from  foot-and-mouth  disease  or  garget  and 
from  the  nasal  cavities  of  horses  affected  with  glanders, 
are  one  and  all  liable  to  obtain  access  to  milk. 

^  British  Medical  Journal,  September  6,  1873. 

2  Medical  Times  and  Gazette,  June  31,  1863. 

^  Mr.  W.  H.  Power  has  recently  produced  a  report  ("Milk  Scarlatina- 
Reports  to  tlie  Local  Government  Board")  in  wliicli  lie  attempts  to 
establish  a  causative  relation  between  an  outbreak  of  Scarlatina  in  West 
and  North  London,  and  the  consumption  of  milk  of  cows  infected  by  a 
disease  characterized  by  vesicles  and  sores  on  the  udder  and  a  shedding 
in  patches  of  the  hair. 


644  INSPECTION    AND    EXAMINATION    OF    MILK 

Milh  contaminated  hy  water  polluted  with  Organic 
Impurities. 

Apart  altogether  frora  the  great  subject  of  the  poison- 
ing of  milk  by  water  contaminated  with  specifically  infected 
excremental  matter,  and  the  still  larger  one  as  to  whether 
enteric  fever  ever  arises  without  such  specific  infection, 
the  question  often  obtrudes  itself,  as  to  whether  any 
disease  ever  arises  from  the  admixture  with  milk  of 
water  containing  an  excess  of  organic  matter. 

Early  in  1881  I  had  under  my  care  two  or  three 
children  and  a  servant  in  one  family  suffering  from 
aphthous  spots  in  the  mouth,  which  after  a  time  dis- 
appeared, but  were  followed  in  the  children  by  a  swollen 
and  painful  condition  of  the  lips.  The  lips  resembled 
raw  beef,  and  yet  presented  at  the  same  time  a  blistered 
ajDpearance.  The  children  seemed  weak  and  poorly  but 
not  ill.  Everything  was  tried  that  could  be  thought  of 
to  cure  their  lips,  but  nothing  improved  them.  At  length 
the  attention  of  the  household  was  attracted  to  the  milk, 
from  the  fact  that  dirt  was  noticed  floating  in  it  visible 
to  the  naked  eye.  The  milk,  which  was  poor  in  quality, 
was  manipulated  by  the  help  of  the  contents  of  a  shallow 
well  surrounded  by  a  collection  of  farmyard  filth.  The 
water  was  not  considered  sufficiently  good  to  drink,  but 
was  used  in  the  dairy  business.  There  was  no  foot-and- 
mouth  disease  amongst  the  cattle  which  furnished  the 
milk.  The  milk  supply  from  this  dairy  was  stopped,  and 
the  milk  from  a  dairy,  adjoining  which  ran  spring  water 
out  of  a  rock,  was  substituted.  The  change  in  the  milk 
supply  was  attended  by  an  immediate  recovery — a  result 
which  no  remedial  measures  were  able  to  accomphsh. 
Another  family  attended  by  a  medical  friend  was  similarly 
affected  at  the  same  time,  who  were  supplied  from  the 
same  dairy.  A  change  of  dairies  was  in  this  case 
attended   by   an   immediate   recovery.     Unfortunately   a 


INSPECTION    AND    EXAMINATION    OF    MILK 


545 


microscopic  examination  of  the  milk,  which  presented  no 
abnormal  appearances,  was  alone  made.  Soon  after  the 
occurrence  of  these  cases,  viz.  in  April  1881,  the  remark- 
able epidemic  at  Aberdeen  was  announced  of  milk 
contamination,  producing  a  peculiar  form  of  disease  in  8  9 
out  of  112  families,  comprising  322  individuals,  of  which 
three  died,  supplied  with  milk  from  the  dairy  at  Old 
Mill  Eeformatory  School,  near  the  city.  The  symptoms 
of  the  complaint,  as  described  by  Dr.  Beveridge,^  were, 
briefly,  a  period  of  incubation  of  2  to  8  days,  followed  by 
a  sharp  attack  of  pyrexia  (the  temperature  rising  to  a 
considerable  height),  and  by  a  dangerous  prostration ;  a 
succession  of  one  or  more  attacks  at  intervals ;  swellings 
of  the  throat  involving  the  glands  in  succession,  and  in 
some  cases  the  deep  lymphatics  of  the  neck.  It  differed 
from  local  inflammation  in  the  extreme  severity  of  the 
constitutional  symptoms,  in  its  periodical  recurrence  at 
pretty  regular  intervals,  and  in  the  extreme  prostration ; 
whilst  it  was  diagnosed  from  diphtheria  by  the  absence 
of  any  diphtheritic  or  false  membrance,  and  in  its  not 
being  contagious.  The  water  supply  of  the  byre  was  con- 
taminated with  organic  matter  mainly  of  vegetable  origin. 


Analysis  by  Mr   Jamieson. 

GRAINS   PER   GALLON. 

PARTS   PER   MILLION. 

Total  Solids. 

Chlorine. 

Nitrogen  as 
Nitrates. 

Free  Ammonia. 

Alb.  Ammonia. 

4-7 

•7 

•5 

•03 

•21 

Prof.  Y.  Cossar  Ewart  found  in  the  milk  during  its 
period  of  infective  activity  organisms  "  morphologically 
not  unlike  bacillus  anthracis,  ha^dng  the  same  life- 
history."    Eats  inoculated  with  this  milk  and  a  cultivation 

^  "  On  a  peculiar  form  of  Disease  arising  from  Milk  Contamination." 

2  N 


546  IXSPECTIOX    AXD    EXAMIXATIOX    OF    MILK 

of  it  containino;  these  bacilli,  died  in  from  15  to  20  hours. 
Pus  obtained  from  an  induration  in  the  neck  of  one  of  the 
patients,  wliich  ended  in  suppuration,  was  found  to  con- 
tain these  bacilli,  and  a  rat  inoculated  with  this  pus  died, 
and  these  bacilli  were  discovered  in  its  tissues.  These 
observations  were  safe-guarded  with  control  experiments.-^ 

The  milk  when  chemically  examined  by  Prof.  Brazier 
yielded  no  abnormal  results,  but  possessed  a  somewhat 
rank  odour.  The  amount  of  milk  consumed  by  the  custo- 
mers and  inmates  of  the  Eeformatory  was  daily  in  excess 
of  the  actual  yield  of  the  cows  by  12  imperial  gallons, 
but  this  fact  was  partly  explained  by  the  purchase  of 
small  quantities  from  the  neighbouring  farmers. 

The  conclusions  of  the  Commissioners,  medical  and 
legal,  were : — 

1.  That  the  epidemic  was  caused  by  poisonous  organic 
matter  contained  in  the  milk ; 

2.  That  the  milk  when  taken  from  the  cows  was 
innocuous ; 

3.  That  poisonous  organisms  were  contained  in  the 
cistern  ^  in  the  b}Te,  and  in  the  water  passing  through 
the  cistern,  and  were  thence  communicated  to  the  milk. 

This  epidemic  of  Aberdeen  bears  a  striking  similarity 
to  the  epidemics  of  "  false  diphtheria  "  which  the  author 
has  seen  in  Essex,  a  disease  which  was  described  by  him 
in  1878,  and  which  appeared  to  spread  through  the 
medium  of  water  polluted  with  organic  matter.^ 

1  ' '  On  a  new  form  of  Febrile  Disease  associated  -witli  the  presence  of  an 
organism  distributed  %Titli  milk,"  in  Froc.  Royal  Socy.,  Xo.  215,  1881. 

^  The  detailed  Keports  of  Profs.  Ewart  and  Brazier  do  not  prove  that 
the  poisonous  bacillus  or  its  spores  were  discovered  in  the  water.  It  is  no 
doubt  a  matter  of  regi'et  that  the  water  Avith  which  the  milk  cans  were 
rinsed  was  not  submitted  to  cultivation  experiments  similar  to  those  to 
which  the  milk  was  subjected. 

^  A  Dozen  Papers  on  Disease  Prevention,  published  by  J.  and  A. 
Churchill. 


APPENDIX 


DISTILLED  WATER  AND  CHEMICALS. 

It  is  very  important  to  be  well  supjilied  with  an  ample  quantity  Distilled 
of  recently  distilled  water,  free  from  ammonia,  and  to  be  enabled  ^^*«^'- 
to  prepare  it  oneself  expeditiously  and  cheaply.  The  distilled 
water  sold  in  chemists'  shops  is  perfectly  worthless  for  analytical 
purposes  when  it  is  necessary  to  estimate  quantities  of  ammonia, 
for  commercial  distilled  water  is  simply  water  freed  from  the 
greater  part  of  its  saline  matters.  It  generally  contains  more  or 
less  ammonia.  The  analyst  simply  requires  a  large  glass  retort 
and  a  zinc  vessel  containing  a  worm  to  act  as  a  condenser  when 
full  of  water.  The  best  water  to  use  for  distillation  is  the  purest 
spring  water.  If  such  water  is  not  conveniently  obtainable  in 
abundance,  the  purest  water  which  contains  the  least  amount  of 
saline  matter  should  be  selected.  Some  analysts  add  a  little 
carbonate  of  soda  to  the  water  which  they  distil.  It  is  better  to 
boil  the  water  in  a  glass  than  in  a  metallic  vessel,  for  the  saline 
residue  which  lines  its  sides  can  be  more  readily  removed  by  an 
acid  from  glass.  The  first  ^  and  last  portions  of  the  retort  of 
water  which  we  distil  should  be  rejected.  We  should  not  begin 
to  collect  the  distilled  water  until  it  passes  over  quite  free  from 
ammonia,  which  can  easily  be  ascertained  by  treating  (say  50  c.  c.) 
with  2  c.  c.  of  Nessler  test.  Distilled  water  will  generally  give 
off  some  little  ammonia  if  re-distilled,  so  difficult  is  it  to  get  rid  of 
all  traces  of  this  body.  If  it  is  requisite  to  procure  water  of  the 
greatest  purity,  it  is  necessary  to  distil  twice-distilled  water  with 
alkaline  permanganate  of  potash,  taking  care  that  this  salt  when 
dissolved  is  perfectly  free  from  ammonia.  If  this  solution  cannot 
be  guaranteed  to  be  thus  exempt,  it  shoidd  be  boiled  for  a  short 
time  previous  to  emjoloyment. 

^  This  impure  distilled  water  will  be  found  to  be  very  useful  for  water 
baths. 


548 


APPENDIX 


Purity  of 
chemicals. 


All  solutious  and  chemicals  should  be  of  the  greatest  purity. 
Chemicals  adapted  for  analytical  piu'poses  are  sold  by  Messrs. 
Hopkins  and  Williams  of  Cross  Street,  Hatton  Garden,  London. 
The  chemicals  of  Kahlbaimi  of  Berlin  are  obtainable  through 
Messrs.  Burgoyne,  Burbidges  and  Co.  of  Coleman  Street,  London. 
The  Medical  Officer  of  Health  should  prepare  his  distilled  water, 
and  all  his  standard  solutions,  except  the  Nessler  reagent,  for  the 
reason  specified  on  page  216.  If  he  wishes  to  avoid  the  labom'  of 
making  the  standard  solutions,  he  can  procure  them  from  Sutton  of 
Norwich.  The  apparatus  may  be  procured  from  Messrs.  Townson 
and  Mercer,  Bishopsgate  Street ;  Messrs.  Cetti  and  Co.,  Brooke 
Street,  Holborn;  F.  W.  Hart  of  Kingsland  Green ;  Messrs.  Burgoyne, 
Bm'bidges,  and  Co.  of  Coleman  Street ;  Messrs.  J.  Allen  and  Co. 
of  Marylebone  Street,  London;  and  from  Dr.  H.  Eohrbeck,  100 
Friedrich  Strasse,  Berlin. 


Apparatus.    RetortS  (2).- 


LIST  OF  APPARATUS  REQUISITE. 

-Capacity  rather  more  than  1|-  litre  (about  48  ounces), 
one  being  for  distilling  sample,  and  the  other  for 
making  distilled  water. 

Liehig's  Condensers  (3). — A  large-sized  one  for  ammonia  process, 
a  medium-sized  one  for  Thorp's  process  for  nitrates, 
and  a  small  glass  condenser  for  air  analysis. 

Nessler  Glasses  (10). — Marked  to  measure  50  c.  c. 
Bell  Metal  Clamjos  (3).— Expensive  but  indispensable. 

Burette. — Capacity  50  c.  c,  graduated  to  -^^thB,  with  an  accurately 
ground  tap  at  one  end  and  a  glass  stopper  at  the 
other. 

Burette. — Capacity  5  c.  c,  the  —^th.  divisions  being  widely  apart. 

Burette  graduated  in  Grains. 

Burette. — 100  septems,  graduated  in  100  parts. 

Galvanized  Iron  Retort  Stands  (3). 

Gmelin^s  Wash  Bottle. — Medium  size. 

Measuring  Flashs. — 1  litre,  500  c.  c.  =  |-  litre,  250  c.  c,  100  c.  c, 
70  c.  c,  50  c.  c,  25  c.  c,  and  |  deci-gallon  flask. 

Bunsen's  Burners  (3). — One  large,  one  small,  one  small  with 
chimney. 


APPENDIX  549 

Analytical  Balance,  in  a  glass  case,  with  weights.  The  balances 
of  Becker  of  New  York  are  good  and  cheap.  The 
weights  made  by  Oertling  are  unsurpassed. 

Flasks  with  welted  mouths  for  corks. 

Indiarubher  Corlcs. — Various  sizes. 

Filter  Papers,  cut,  German,  which  will  not  permit  the  precipitate 
of  sulphate  of  baryta  to  pass  through  them. 

Soxhlefs  Fat  Extractor. 

Platinum  Dish,  of  a  capacity  of  about  100  c.  c. 

„         Crucible. 

„         Dishes  (3)  small,  for  milk. 

Berlin  Evaporating  Dishes  (6),  about  4  inches  in  diameter.  A 
nest  of  dishes  of  a  smaller  size. 

White  Porcelain  Tiles  (2),  about  5  inches  square. 

Pip)ette,  with  bulb  in  centre,  and  marked  with  file  to  indicate  2 
c.  c.  for  Nessler  test. 

„       with  bidb  of  capacity  of  5  c.  c.  for  milk. 

Pipettes  (3),  of  the  capacity  of  5  c.  c,  and  graduated  to  xV^^^^  i 
one  for  nitrate  of  silver  sol.,  another  for  preparing 
ammonia  standard,  and  the  third  necessary  in  the 
quantitative  determination  of  nitrates  and  nitrites. 

Pipette  (1)  of  the  capacity  of  10  c.  c,  and  graduated  to  xtj*-'^^ 
for  the  standard  soap  solution. 

Pipettes  (2  or  3). — Graduated  in  septems  and  grains. 

Steam  Co7idenser  for  preparing  distilled  water,  made  of  zinc,  con- 
taining worm.  It  is  filled  with  cold  water.  A 
retort,  in  which  the  water  is  boiled,  should  be  con- 
nected with  it. 

Beakers. — A  nest  of  different  sizes. 

Adapters  (2). 

Funnels. — One  large  and  several  small. 

Sample  Bottles  (36). — Stoppered.     Made  of  stout  glass. 

Tripods  (2). 

Wire  Gauze  (2). — Pieces  of  coarse  and  fine,  each  about  4  inches 
square. 

Pipe  Triangles  (6). 


550  APPENDIX 

Copjper  Water  Baths  (2). 

Receiver  for  estimation  of  nitrates,  which  resembles  a  very  large 
Nessler  glass.  Marks  with  file  should  indicate  50 
c.  c.  and  100  c.  c. 

Glass  Rods  of  different  sizes. 

Tongs  for  laboratory. 

Watch  Glasses. 


RULES  FOR  INTERCHANGE  OF  DIFFERENT  EXPRESSIONS  OF 
RESULTS  OF  ANALYSIS. 

To  convert  parts,  per  100,000,  into  grains  per  gallon  (  =  parts  per 
70,000),  multiply  by  -7. 

To  convert  grains  per  gallon  ( =  parts  per  70,000)  into  parts  per 
100,000,  divide  by  -7. 

To  convert  parts  per  million,  or  milligrammes  per  litre,  into  grains 
per  gallon,  multiply  by  '07. 

To  convert  grains  per  gallon  into  parts  per  million,  or  milligrammes 
per  litre,  divide  by  •07. 

To  convert  parts  per  100,000  into  parts  per  million,  or  milligrammes 
per  litre,  multij)ly  by  10. 

To  convert  parts  of  nitric  acid  into  parts  of  ammonia,  multiply  by 
17  and  divide  by  63. 

To  convert  parts  of  ammonia  into  parts  of  nitric  acid,  multiply  by 
63  and  divide  by  17. 

To   convert   parts   of  nitric   anhydride   into  parts   of  ammonia, 
multiply  by  17  and  divide  by  108. 

To  convert  grammes  per  litre  into  grains  per  gallon,   multijDly 
by  70. 

To  convert  parts  of  free  ammonia,  or  ammonia  from  alb.  ammonia, 
into  parts  of  nitrogen,  midtiply  by  14  and  divide  by  17. 

To  convert  "  nitrogen  as  ammonia "  into  free  ammonia,  multiply 
by  17  and  divide  by  14. 

To    convert    "  nitrogen   as   alb.    ammonia "   into   alb.    ammonia, 
multiply  by  17  and  divide  by  14. 

To  bring  cubic  inches  into  gallons,  multiply  by  40  and  divide  by 
11,091,  or  multiply  at  once  by  '003607. 


APPENDIX  551 

RULES  FOE,  CONVERSION  OF 

DEGREES  OF  ONE  THERMOMETER  SCALE  INTO 

THOSE  OF  ANOTHER. 

Fahr.  into  Cent. — Divide  by  9,  multiply  by  5  and  deduct  32. 
Cent,  into  Fahr. — Multiply  by  9,  divide  by  5  and  add  32. 
Falir.  into  Rdaumur. —Divide  by  9,  multiply  by  4  and  deduct  32. 
Rdaumur  into  Fahr. — Divide  by  4,  multiply  by  9  and  add  32. 


METRICAL  WEIGHTS  AND  MEASURES. 
Weight. 
1  mUligramme  =  '015432  grain. 
1  centigramme  =  -\?) 4:^2  grain. 
1  decigramme  =1'^4:^2  grains. 
1  gramme  =  \b-i'?>2  grains  =  weight  of  a  cubic  centimetre  of  water 

at  39-2°  Fahr. 
1    Mo^ramme  =  15432 '348   grains  =  1000   grammes  =  2-2   lbs. 
(Av.) 

Capacity, 

1   cubic  centimetre  =  15' 4:32  grains  =  16-9  minims  =  "06103  cubic 

inch. 
1  litre  =15 4:32 '3 4:8  grains  =  1  pint  15  ozs.  2  drs.  and  11  minims 

=  61  "027    cubic    inches  =  1000    cubic    centimetres  =  35'3 

ounces  =-22  gallon  = -035316  cubic  foot  =  1000  grammes  = 

1,000,000  milligrammes. 
1  ounce  =  28'35  cubic  centimetres  =  1 '733  cubic  inch. 
1  citbie  inch=  16  "4  cubic  centimetres. 
1  ciibic  foot  =  28-31  litres  =  1728  cubic  inches. 
1  cuhic  meire  =  1,000,000  cubic  centimetres  =  1,000,000  grammes 

=  1,000,000,000  milligrammes  =  1000  litres  =  35-3   cubic 

feet. 
1  pmi  =  34'59  cubic  inches. 

English  laches.  Length. 

1  millimetre  =  -03%. 
1  centimetre  =  '3*^, 
\  decimetre  =  3-% 4:. 
1  me«re  =  39-37  =  3-28  feet. 

1  Momefre  =  1000   metres  =  1094    yards  =  -62   mile  =  3280   feet 
and  10  inches. 


552  APPENDIX. 

Area. 
1  square  millimetre  =  "0015  square  inch. 
1  square  centimetre  =  '154:  square  inch. 
1  square  metre  =  154:2  Bqiiaxe  inches  =  10*76  square  feet. 

JV.B. — The  Latin  prefix  indicates  division,  and  the  Greek 
prefix  indicates  multiplication. 

1  Septem  =  7  grains  =  "  decimillen." 

1  Pmmd  (Ay.)     =  7000  grains. 

1  Gallon  (Imp.)  =70,000  grains. 

1  Decern  =10  grains. 

•|  Deci-ffallou       =  3500  grains. 

1  minim  weighs  -91  grain. 

1  fluid  drachm  weighs  54-68  grains. 

\  flidd  ounce,  weighs  437-5  grains. 


INDEX 


Aberdeen,  outbreak  at,  and  milk,  545. 
"Absorbers,"  or  "  barboteurs,"  319. 
Aeroscope,  Pouchet's,  297. 

pump,  298. 
Ages,  mortality  at  different,  402,  403. 
Ague  and  seasonal  meteorology,  391. 
Air  analysis,  219. 

,,         pulverization  of  water,  method  of,  322 

atmospheric  pressure  of,  407. 

biological  examination  of,  340. 

carbonic  acid  in,  227. 

carbonic  oxide  in,  247. 

chemical  examination  of,  310. 

churchyard,  268. 

composition  of,  224. 

compressed,  therapeutic  employment  of,  377. 

continual  pollution  of,  246. 

copper  in  the,  343. 

dust  in  atmospheric,  294. 
,,     collector  of  Dr.  Cunningham,  298. 

electrical  state  of  the,  434. 

hygrometric  state  of  the,  422, 

„  „  and  health,  369. 

impure  and  respiratory  diseases,  283. 

impurities  sus^^ended  in,  258. 

lead  in  the,  343. 

marsh,  268. 

microscopic  examination  of,  301. 

nitrous  acid  in,  357. 

observations  in  Glasgow,  318. 


554  INDEX 

Air  of  our  houses,  270. 

,,  ,,       its  deterioration,  273. 

,,      rooms,  372. 
,,      streets,  277. 
organic  matter  in,  232,  312. 
oxj^gen  in,  225. 
peroxide  of  hydrogen  in,  357. 
pressure  of  the,  374. 
purity  of,  221. 
solid  bodies  in,  292. 
standard  of  pure,  285. 
subsoil,  267. 
temperature  of  the,  411. 

,,  ,,         and  health,  362. 

Avashings,  236,  314. 
Ammonia,  91. 

albuminoid,  estimation  of,  44. 
excess  of  in  pure  waters,  92. 
free  or  saline,  estimation  of,  40. 
standard  solution  of,  217. 
Animal  impurities  in  air,  258. 
Animals,  diseases  of,  447. 
Anthraeic  diseases  and  meat,  458. 
,,  ,,       and  milk,  540. 

Anti-cyclones,  360. 
Aphthous  fever,  536. 
Apparatus,  chemical,  requisite,  548. 

steaming,  78. 
Arsenic  in  the  air,  343. 

in  the  articles  of  the  household,  261, 
in  wall  papers,  260,  344. 

,,  Davy's  sodium  amalgam  test  for,  347. 

,,  Marsh's  test  for,  346. 

Asparagus,  poisonous,  486. 
Aspirators,  317,  319,  320. 
Asthma  and  seasonal  meteorology,  396. 


B 

Bacillus  Anthracis,  306. 

Comma-shaped,  306 
Tuberculosis,  306. 
Bacteria  in  air,  307. 

in  water,  161. 
of  a  hospital,  308 


IXDEX  555 


Barley,  testa  of  grain  of,  501. 

Barometric  pressure,  its  determination,  407. 

Baryta  water,  store  bottle  for,  338. 

Bath  chemical  for  condemned  flesh,  485. 

Bench  marks,  406. 

Biological  method.  Air,  340. 

,,  ,,  "Water — Frankland's,  76. 

Koch's,  74. 
,,  ,,  ,,  Smith's,  75. 

Braxy  meat,  460. 
Bread,  adulterations  of,  509. 
alum  in,  510,  516. 
examination  of,  508. 

,,  chemical,  513. 

,,  microscopic,  509. 

foul  and  machine-made,  509. 
lime  and  magnesia  compounds  in,  511. 
sulphate  of  copper  in,  512. 
Bronchitis  and  seasonal  meteorology,  396. 
Brucine  test  for  nitric  acid,  109. 
"  Bunt,"  in  corn,  491. 

c 


Caeboxic  acid  in 

air, 

240. 
estimation  of. 

328. 

Abney's  method. 

332. 

Household    ,, 

33.3. 

Minimetric  ,, 

335. 

Montsouris  ,, 
Pettenkofer's  ,, 

329. 

328. 

"Wanklyn's      ,, 

331. 

oxide  in  air,  247. 
test  for,  252. 
Cattle  plague  and  meat,  457. 
,,         ,,       and  milk,  535. 
Certificate  of  W.  A.  used  by  analysts,  214. 

,,  ,,  ,,        health  officer,  213. 

Cesspool  filth,  diagnosis  of,  in  water,  210. 
Chemicals  requisite,  548. 
Chlorine,  determination  of  the,  135. 
Cholera  and  seasonal  meteorology,  395. 
Codfish,  poisonous,  481. 
Coke  as  a  fuel,  249. 
"Cold  sp)ells,"  365. 
Colonies,  enumeration  of,  84. 


556  INDEX 

Colour  test  for  water,  20. 

Copper  in  water,  159. 

Corn,  examination  of,  489. 

Cover  glass  preparations  of  water,  161. 

Cyclones,  359. 

D 

DAjrp  Chamber,  83. 

Darnel  gi-ass,  testa  of  grain  of,  506. 

Data  on  wliicli  to  form  an  opinion  respecting  a  water,  195. 

Density  of  population  and  mortality,  223. 

Diarrhoea  and  dysenter}^,  and  seasonal  meteorology,  391. 

autumnal,  392. 
Diphtheria  and  poultry,  479. 

and  seasonal  meteorology,  398. 
Distilled  water,  preparation  of,  547. 
District  standards,  196. 
"Drop  cultures,"  162. 
Dublin,  temperature  of,  362. 
Dust  of  the  air,  301. 
Duties  of  medical  officer  of  health,  4. 
Dysentery  and  seasonal  meteorologj',  395. 

E 

"Eae  Cockle"  in  corn,  490. 
EdinlDurgh,  temperature  of,  362. 
Electricity,  atmospheric,  434. 

,,  ,,  positive  and  negative,  439, 

,,  ,,  water-dropping  collector  of,  436. 

Electrometer  quadrant,  436. 
Enteric  fever  and  milk,  520. 

,,  ,,     and  seasonal  meteorology,  390. 

Ergot  of  rye,  490. 

Erysipelas  and  seasonal  meteorologj^,  399. 
Excremental  fdth  in  air,  255. 


FAPa>'AGEOUS  foods,  nutritive  values  of,  494. 

Fat  of  milk,  estimation  of,  with  Soxhlet's  extractor,  530. 

Fever  and  seasonal  meteorology,  389. 

surgical,  381. 
Fish,  inspection  of,  480. 
Fish-like  odour  of  waters,  17. 


INDEX  557 

Flesli,  condemned,  destruction  of,  484. 
Flour,  acarus  farinse  in,  500. 
alum  in,  497. 
examination  of,  493. 

,,  cliemical,  495. 

,,  microscopic,  499. ' 

metallic  poisons  in,  499. 
FMce  in  meat,  475. 
Food,  the  purity  of,  443. 
Foot-and-mouth  disease,  and  meat,  456. 
,,  ,,  ,,        and  milk,  536. 

Forchammer  process,  an  improved  quantitative,  38. 
Franklaud  and  Armstrong  process,  53. 

,,  ,,  and  Wanklyn  processes  compared,  63. 

Fruit  and  vegetables,  inspection  of,  486. 
Funnel,  hot  water  for  filtration,  77. 
Furnishing  materials,  poisonous,  261. 

G 

Game,  inspection  of,  478. 

Garget,  542. 

Gases,  poisonous,  defiling  air,  257. 

Glasgow,  observations  on  air  in,  318. 

Grand val  and  Lajoux's  process  for  nitric  acid,  120. 

H 

Hadow-Hoesley's  test  for  alum  in  bread,  517. 

Ham,  poisonous,  477. 

Hardness,  determination  of  the,  139. 

Hard  waters,  influence  on  health,  142. 

Health  and  extremes  of  temperature,  364. 

and  low  temperatures,  364. 
Height,  corrections  for,  to  barometric  readings,  409. 
Heisch's  test,  24. 

Horsley's  test  for  nitrates  and  nitrites,  106. 
Hospitals,  modern  pattern,  374. 
Hydrophobia,  and  seasonal  meteorology,  399.  '   . 

Hygrometer,  Lowe's,  426. 

Mason's,  424. 
Hygrometry,  422. 


iNCtTBATOE,  82. 

Indigo  process  for  estimating  nitrates,  112. 


5  58  INDEX 

Insanity  and  seasonal  meteorology,  400. 
Intermittent  fever  and  seasonal  meteorology,  391 
Iron  in  water,  157. 

K 

"Keeping  Powers "  of  a  water,  19. 

Knife-grinders  of  Sheffield,  262. 

Koch's  biological  method  for  the  examination  of  water   74. 

Kubel's  permanganate  of  potash  process,  27 


Lamb,  immature,  476. 

Lead  in  articles  of  the  household,  262. 

Lead  in  water,  156. 

London,  mortality  of,  402, 

temperature  of,  362. 

Magnesia,  determination  of  the,  145. 
Measles  and  seasonal  meteorology,  384. 
"Measly"  meat,  468. 
Meat  and  accidents,  463. 

characters  of  good  and  bad,  450. 

diseased,  arguments  for  and  against  its  employment,  463,  464. 
,,         resurrection  of,  484. 
Memoranda  for  water  analysts,  185. 
Metallic  impurities  in  air,  258,  343. 
Metals,  poisonous,  determination  of,  154. 
Meteorological  observations,  registration  of,  439. 
Meteorology  and  health,  358. 

seasonal  and  disease,  380. 
Metrical  weights  and  measures,  551. 
Micro-organisms,  305. 

in  London  waters,  85. 
Microscopic  examination  of  air,  301 . 

,,  ,,  water,  161. 

Microzjmie  test,  25. 
MUk,  abnormal,  533. 

and  aifections  of  mouth  and  throat,  544. 

and  typhoid  fever,  520. 

blue,  524. 

changes  in  taste  and  odoivr  of,  525. 

containing  tubercle  bacilli,  542. 


INDEX 


559 


Milk,  examination  of,  520. 

chemical,  525. 

estimation  of  fat,  528. 

microscopic,  522.  _ 

excretions  and  secretions  of  diseased  animals,  tainted  with,  o43. 
fever,  461. 
"fore,"  533. 

of  diseased  animals,  535. 
organic  impurities,  contaminated  with,  544. 
physical  peculiarities  of,  523. 
reddish,  524. 
scarlatina,  543. 
Society  of  Analysts,  processes  and  standards,  52/. 

"whole,"  533. 

yellow,  523. 
Mineral  impurities  in  air,  258. 
Miners,  Cornish,  mortality  of,  258. 
Mistakes  of  water  analysts,  177.  o-tTo^i 

Montsouris  Observatory,  apparatus  employed  at,  317,  341. 

observations  on  air  at,  228,  304,  307. 
Mortality  and  density  of  population,  222.  ,„^    ,,,0 

Mortality  at  different  ages  and  seasonal  meteorology,  402,  403. 
of  the  sexes,  >  >  " 

N 

Nessler  reagent,  216. 
Neuralgia  and  meteorolog}^  360. 
New  York,  mortality  of,  403. 

Nitrates  and  Nitrites,  qualitative  examination  for,  10b. 
„  quantitative         ,,  >>     Hi- 

"  ^  utility  of  the  estimation  of  the,  100. 

Nitric  acid,  the  Brucine  test  for,  109.  _ 

the  sulphophenic  acid  process  for  the  estimation  of,  120. 

Nitroo-en,  as  nitrates  and  nitrites,  95. 

°  ^^  ,,       in  different  strata,  98. 

"  "  ^^       objections  to  estimation  of,  99. 

"  "  rxiies  for  guidance  in  the  estimation  of,  122. 

Nitrous  acid,  the  metaphenylene  diamine  test  for,  110. 

the  napthylaniine  hydrochloride  test  for,  357. 
",      the  potassium  iodide  and  starch  test  for,  110. 


0 


Oat,  testa  of  grain  of,  506. 
Odour,  cucumber,  of  water,  18. 
fish-like,  of  water,  17. 


6    0  INDEX 

Odour  of  different  diseases,  303. 
Old  age  and  seasonal  meteorology,  405. 
Operations,  time  favourable  and  unfavourable  for,  382. 
Opinion,  formation  of,  as  to  a  water,  188. 
Ordnance  bencb  marks,  406. 
Organic  niti'ogen  and  carbon,  56. 
matter  in  air,  232. 

,,  Remsen's  collector  of,  321. 

,,  Smee's  ,,  322. 

matter  in  water,  13. 

,,  recent  or  decomposing,  205. 

Overcrowding  and  disease,  282. 
Oxygen  dissolved,  estimation  of,  86. 

process,  26. 
Ozone,  estimation  of,  349. 

test  papers,  fallacies  of,  352. 
Ozonometry,  errors  of  old  method,  355. 


PaPuAFFix  in  drinking  water,  1 7. 
Parturient  apoplexy  and  meat,  461. 
Parturition  or  milk  fever,  and  milk,  542. 
Peaty  water,  diagnosis  of  a,  205. 
,,         ,,      objections  to,  190. 
Pericarditis  and  seasonal  meteorology,  401. 
Permanganate  and  caustic  potash  solution,  218. 
of  potash  process,  qualitative,  26. 

,,  quantitative,  26. 

,,  ,,         an  improved,  38. 

„  , ,         Drs.  Letheby's  and  Tidy's,  28. 

,,  „         Drs.  Woods'  and  F.  de 

Chaumont's,  33. 
Phosphates,  determination  of  the,  150. 
Phthisis  pulmonalis,  279, 

,,  ,,  and  seasonal  meteoi'ology,  398. 

Plate  cultivations,  81. 
PI  euro-pneumonia  and  meat,  454. 
Pneumonia  and  seasonal  meteorology,  396. 
Poisoned  animals,  meat  of,  482. 
Poisonous  gases,  257. 
Pond  water,  190. 
Pork,  poisonous,  477. 
Poultry,  game,  etc.,  inspection  of,  478. 
Previous  sewage  contamination  of  water,  57. 


INDEX 

Processes  of  Avater  analysis  compared,  63. 

,,  ,,        value  of,  71. 

Provisions,  tinned,  488. 

Pueri^eral  fever  and  seasonal  meteorology,  400. 
Putrefactive  processes,  defiling  air,  254. 


Radiation,  Solar,  367. 

Rain,  albuminoid  ammonia  in,  239. 

-band,  428. 

guage,  423. 

water,  11,  207. 
Rainey's  bodies  in  meat,  474. 
Record  of  analyses,  175. 
Eeport,  preparation  of,  212. 
Rheumatism  and  seasonal  meteorology,  401. 
Rinderpest  and  meat,  457. 
and  milk,  535. 
Rust  in  corn,  492. 

S 

Samples  of  water,  collection  of,  170. 

Sarcinte,  306. 

Sausages,  poisonous,  477. 

Scarlatina  and  seasonal  meteorology,  387. 

Scarlet  fever  and  meat,  462. 

Sewage  emanations,  defiling  air,  255. 

in  water,  210. 
Sewer  gas,  pollution  of  water  with,  137. 
Sexes,  mortality  of  the,  and  seasonal  meteorology,  404. 
Silver,  nitrate  of,  standard  solution  of,  218. 
Smallpox  and  seasonal  meteorology,  383. 

of  sheep  and  meat,  457. 
Smell  of  a  water,  14. 
"Smut"  in  corn,  491. 
Soap,  standard  solution  of,  216. 
Soil,  porosity  of,  264. 
Solar  radiation,  367. 
Solid  bodies  in  air,  292. 
Solid  residue,  determination  of,  124. 

,,         ,,         ignition  of,  128. 
Solutions,  standard  for  water  analysis,  216. 
Spectroscope  in  hygrometry,  427. 
2   0 


561 


INDEX 

Splenic  apoplexy  and  meat,  458. 
Standard  of  pure  air,  224. 

,,  ,,     water,  10. 

"Standards,  district,"  196. 
Starches,  various  kinds  of,  500-505. 
Starch  tests  for  nitrous  acid,  110. 
Sterilizer,  hot  air,  79. 

steam,  78. 
Stoves,  cast  and  wrought  iron,  250. 
Sulphates,  determination  of  the,  147. 

,,  ,,  ,,        Houzeau's  process  for  the,  148. 

Surgical  fever  and  meteorology,  381. 
Swine  plague  and  meat,  462. 


Teeth,  caries  of  the,  495. 

Temperature,  corrections  for,  to  barometric  readings,  409. 
extremes  of,  364,  379. 
its  detei'mination,  411. 
management  of  children  and,  367. 
Thermometer  scales,  conversion  of,  551. 
solar  max.,  414. 
stands,  412.      ' 
terrestrial  min.,  415. 
Thermometers,  markings  of  degrees  of,  420. 

verification  of,  417. 
Thorp's  process  for  estimation  of  nitrates,  114. 

,,  ,,        expeditious  modification  of,  119. 

Time  occupied  in  performing  an  analysis,  172. 
Tinned  provisions,  488. 
Trichina  spiralis  and  meat,  469. 

,,  ,,        modes  of  detection  of,  473. 

Tiichinosis  and  enteric  fever,  471. 
Tubercular  diseases  and  meat,  461. 
,,  ,,       and  milk,  540. 

Typhoid  fever  and  meat,  462. 
,,  ,,     and  milk,  520. 

,.  ,,      and  seasonal  meteorologj^,  390. 

Typhus  fever  and  ,,  ,,  389. 


u 

Urine  in  water,  209. 


INDEX  563 

V 

Valuation  tables,  196. 
Vapours,  injurious,  257. 
Veal,  immature,  476. 
Vegetable  impurities  in  air,  258. 
Ventilation,  284,  288. 

absence  of,  278. 

through  walls,  287. 
Vibrio  tritici  in  corn,  490. 
Volatile  matters,  amount  of,  in  a  water  residue,  132. 

w 

Wall  Papers,  260,  344. 

Wanklyn,  Chapman,  and  Smith  process,  39. 

Water  analysis,  7. 

,,         comparison  between  processes  of,  63. 
,,         value  of  processes  of,  71. 
animal  organic  matter  in,  203. 
colour  of  a,  20. 
good  artesian  well,  11. 
,,     rain,  11. 
,,     shallow  well  J  11. 
,,     spring,  10,  201. 
microscopic  examination  of  a,  161. 
polluted  by  sewage,  210. 

,,       by  sewer  gas,  137,  206. 
,,       by  urine,  209. 
suspicious,  201. 

vegetable  organic  matter  in,  204. 
wholesomeness  of  a,  9. 
Waters,  different  classes  of,  11,  58. 
Weevil  in  corn,  489. 
Wheat  midge,  490. 

testa  of  grain  of,  501. 
Whooping-cough  and  seasonal  meteorology,  386. 
Wigner's,  Mr.,  valuation  table,  196. 
Wind,  direction  of  the,  and  health,  378. 

,,  ,,        and  strength  of  the,  430. 

Woolsorters'  disease,  309,  459. 

z 

Zinc  in  water,  159. 
Zymotic  test,  25. 


Printed  by  R.  &  R.  Clark,  Edinhtrgh 


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